Eligibility of PBS dependent ILR

[rsh08]

Hi,
Hope to get a confirmation from the forum on below ILR query.

Eligibility to apply for ILR for PBS dependent with main applicant in Tier2 General.
Here's the details:
Person A (main applicant) T2 General - Started Aug18 to Aug23
Person B (spouse) PBS Dependent - Started Sep18 to Aug23

(A) got Tier2 General in Aug 2018 and entered UK in Aug2018
(B) was already in UK on previous ICT visa later became PBS dependent of (A) from Sep18 to Aug23. Hence no re-entry in UK required.

Questions:
1. (B) is running 1 month behind (A) to qualify for ILR under 5 years eligibility period.
2. Can (B) still apply for ILR under 5 year route with main applicant (A) in same application?
3. If so, is Set (O) the right form to apply for both?
4. Or, do (B) need to wait for a month to become eligible and apply later separately?

Looking forward to hearing from experts and anyone who has gone through similar situation recently.

Thanks in advance.

[zimba]

The dependant better apply later when eligible using form SET(O)