*** First and foremost, apologies

I am on a Skilled Worker Visa valid until Jan 2023. I am due to apply early for ILR in Sept 2022.
My spouse is on PBS dependant visa valid until Sept 2022; he cannot apply for ILR until Sep 2025 (his clock was reset due to change of visa category in 2020). As his PBS dependant visa is expiring in Sept 2022, he will extend his visa.
Here are my list of queries and I humbly request your guidance.
1. Given that his PBS dependant visa extension application needs to have my Skilled Worker visa details, and also since his new BRP should not be having the validity of my current BRP (Jan 2023) but it needs to be having the validity of 3 years from Sept 2022 (i.e. Sept 2025), when should he submit his extension application?
a) As soon as I have submitted (and paid for) my ILR application OR
b) As soon as I have made the appointment for biometrics at UKVCAS OR
c) As soon as I have uploaded the relevant documents prior to my biometrics OR
d) As soon as my biometrics appointment is done OR
e) As soon as I get the result of my ILR (assuming it is a positive outcome!)
2. Whilst filling in his visa extension application draft, I came across a few curveball questions. Here XYZ = me. ABC = my dependant spouse.
a. Which visa or permission to stay has XYZ applied for or been granted?
Answer: Skilled Worker
b. Do you have one of these Home Office reference numbers for XYZ?
Answer: XYZ's BRP number has been provided
c. Does XYZ already have their Skilled Worker immigration permission?
I am clueless as to what to put here since 2a and 2b clearly provides them with the required info. Am I missing anything here?
d. Has ABC ever been given medical treatment in the UK?
He has had COVID vaccines and NHS required 40+ health check. In that case, should he be answering YES or NO to this question.
Thanks for your guidance!
