diff --git a/src/libs/WorkflowUtils.ts b/src/libs/WorkflowUtils.ts
index 07f525b403fb..a6109820873e 100644
--- a/src/libs/WorkflowUtils.ts
+++ b/src/libs/WorkflowUtils.ts
@@ -10,6 +10,7 @@ import type ApprovalWorkflow from '@src/types/onyx/ApprovalWorkflow';
 import type {PersonalDetailsList} from '@src/types/onyx/PersonalDetails';
 import type PersonalDetails from '@src/types/onyx/PersonalDetails';
 import type Policy from '@src/types/onyx/Policy';
+import type PolicyEmployee from '@src/types/onyx/PolicyEmployee';
 import type {PolicyEmployeeList} from '@src/types/onyx/PolicyEmployee';
 import {isBankAccountPartiallySetup} from './BankAccountUtils';
 import {convertToDisplayString} from './CurrencyUtils';
@@ -80,6 +81,16 @@ function calculateApprovers({employees, firstEmail, personalDetailsByEmail}: Get
     return approvers;
 }
 
+/** Build a Member from a policy employee using personal details for avatar/displayName */
+function buildMemberFromEmployee(employee: PolicyEmployee, personalDetailsByEmail: PersonalDetailsList, email: string): Member {
+    return {
+        email,
+        avatar: personalDetailsByEmail[email]?.avatar,
+        displayName: personalDetailsByEmail[email]?.displayName ?? email,
+        pendingFields: employee.pendingFields,
+    };
+}
+
 type PolicyConversionParams = {
     /** Policy data containing employees and approver information */
     policy: OnyxEntry<Policy>;
@@ -114,20 +125,23 @@ function convertPolicyEmployeesToApprovalWorkflows({policy, personalDetails, fir
     // Keep track of used approver emails to display hints in the UI
     const usedApproverEmails = new Set<string>();
     const personalDetailsByEmail = lodashMapKeys(personalDetails, (value, key) => value?.login ?? key);
+    const availableMembers: Member[] = [];
 
-    // Add each employee to the appropriate workflow
     for (const employee of Object.values(employees)) {
         const {email, submitsTo, pendingAction} = employee;
-        if (!email || !submitsTo || !employees[submitsTo] || employee.pendingAction === CONST.RED_BRICK_ROAD_PENDING_ACTION.DELETE) {
+        if (!email) {
             continue;
         }
 
-        const member: Member = {
-            email,
-            avatar: personalDetailsByEmail[email]?.avatar,
-            displayName: personalDetailsByEmail[email]?.displayName ?? email,
-            pendingFields: employee.pendingFields,
-        };
+        const member = buildMemberFromEmployee(employee, personalDetailsByEmail, email);
+
+        if (pendingAction !== CONST.RED_BRICK_ROAD_PENDING_ACTION.DELETE) {
+            availableMembers.push(member);
+        }
+
+        if (!submitsTo || !employees[submitsTo]) {
+            continue;
+        }
 
         if (!approvalWorkflows[submitsTo]) {
             const approvers = calculateApprovers({employees, firstEmail: submitsTo, personalDetailsByEmail});
@@ -182,8 +196,10 @@ function convertPolicyEmployeesToApprovalWorkflows({policy, personalDetails, fir
         });
     }
 
-    const availableMembers =
-        policy?.approvalMode === CONST.POLICY.APPROVAL_MODE.BASIC ? sortedApprovalWorkflows?.flatMap((workflow) => workflow.members) : (sortedApprovalWorkflows.at(0)?.members ?? []);
+    // availableMembers built in loop above: all employees with email, excluding pending delete.
+    // Includes members with orphaned submitsTo/forwardsTo so admins can fix chains from Expenses From picker.
+    // See https://github.com/Expensify/Expensify/issues/598876
+    availableMembers.sort((a, b) => localeCompare(a.displayName ?? a.email, b.displayName ?? b.email));
 
     return {approvalWorkflows: sortedApprovalWorkflows, usedApproverEmails: [...usedApproverEmails], availableMembers};
 }
diff --git a/tests/unit/WorkflowUtilsTest.ts b/tests/unit/WorkflowUtilsTest.ts
index faa33b3d9650..f2b665593545 100644
--- a/tests/unit/WorkflowUtilsTest.ts
+++ b/tests/unit/WorkflowUtilsTest.ts
@@ -469,6 +469,78 @@ describe('WorkflowUtils', () => {
             }
             expect(approvalWorkflows).toEqual([defaultWorkflow, secondWorkflow]);
         });
+
+        it('Should include all workspace members in availableMembers', () => {
+            // Simulates ADVANCED approval mode: Alex and Hannah submit to Carolyn (custom workflow),
+            // others submit to Hannah (default). Previously availableMembers only had default workflow
+            // members, excluding Alex and Hannah.
+            const employees: PolicyEmployeeList = {
+                'alex@htc.us': {
+                    email: 'alex@htc.us',
+                    submitsTo: 'carolyn@htc.us',
+                },
+                'hannahw@htc.us': {
+                    email: 'hannahw@htc.us',
+                    submitsTo: 'carolyn@htc.us',
+                },
+                'carolyn@htc.us': {
+                    email: 'carolyn@htc.us',
+                    submitsTo: 'carolyn@htc.us',
+                },
+                'gio@htc.us': {
+                    email: 'gio@htc.us',
+                    submitsTo: 'hannahw@htc.us',
+                },
+            };
+            const policy = createMockPolicy(employees, 'hannahw@htc.us');
+            (policy as Policy).approvalMode = CONST.POLICY.APPROVAL_MODE.ADVANCED;
+            const personalDetailsForTest: PersonalDetailsList = {
+                'alex@htc.us': {accountID: 1, login: 'alex@htc.us', displayName: 'Alex Walker'},
+                'hannahw@htc.us': {accountID: 2, login: 'hannahw@htc.us', displayName: 'Hannah Walker'},
+                'carolyn@htc.us': {accountID: 3, login: 'carolyn@htc.us', displayName: 'Carolyn Smith'},
+                'gio@htc.us': {accountID: 4, login: 'gio@htc.us', displayName: 'Gio'},
+            };
+
+            const {availableMembers} = convertPolicyEmployeesToApprovalWorkflows({
+                policy,
+                personalDetails: personalDetailsForTest,
+                localeCompare,
+            });
+
+            const memberEmails = availableMembers.map((m) => m.email).sort();
+            expect(memberEmails).toEqual(['alex@htc.us', 'carolyn@htc.us', 'gio@htc.us', 'hannahw@htc.us']);
+        });
+
+        it('Should include members with orphaned submitsTo in availableMembers', () => {
+            // Member with submitsTo pointing to non-member (not in employeeList) won't appear in any
+            // workflow, but should still appear in availableMembers so admins can fix the chain.
+            const employees: PolicyEmployeeList = {
+                'alice@example.com': {
+                    email: 'alice@example.com',
+                    submitsTo: 'nonexistent@example.com',
+                },
+                'bob@example.com': {
+                    email: 'bob@example.com',
+                    submitsTo: 'bob@example.com',
+                },
+            };
+            const policy = createMockPolicy(employees, 'bob@example.com');
+            const personalDetailsForTest: PersonalDetailsList = {
+                'alice@example.com': {accountID: 1, login: 'alice@example.com', displayName: 'Alice'},
+                'bob@example.com': {accountID: 2, login: 'bob@example.com', displayName: 'Bob'},
+            };
+
+            const {approvalWorkflows, availableMembers} = convertPolicyEmployeesToApprovalWorkflows({
+                policy,
+                personalDetails: personalDetailsForTest,
+                localeCompare,
+            });
+
+            expect(approvalWorkflows).toHaveLength(1);
+            expect(approvalWorkflows.at(0)?.members).toHaveLength(1);
+            const memberEmails = availableMembers.map((m) => m.email).sort();
+            expect(memberEmails).toEqual(['alice@example.com', 'bob@example.com']);
+        });
     });
 
     describe('convertApprovalWorkflowToPolicyEmployees', () => {