Universal Credit -> Pension Credit

I'm male and reach SR age in roughly six months. I'm in receipt of a workplace pension of £125/mth and have around £60k in a SIPP which is not in drawdown, but I took UFPLS a couple of times over the past couple of years. I also have under £6k in investments.

I'm on UC, supplying "fit notes" though receiving just the standard amount (minus the £125). I've been waiting to hear whether a face-to-face work capability assessment is required for months. I suspected they were delaying because of my impending Pension Credit eligibility, which in fact happened a few days ago. The Jobcentre staff seemed to feel at that point I'd be off their hands, but when I specifically asked my work coach how the UC->PC transition would work he said he didn't know, he'd never seen it before! (TBF he did say he'd find out.)

I applied by phone for PC a few weeks ago and during the call they set up a conference call with the SIPP provider during which it was established that there's no restriction on what I can withdraw. The application was then to be sent to a specialist decision maker, but I've heard nothing since, except:

On the actual day of eligibility, very nearly, I got an information request from the DWP for the SIPP provider that I had to sign and forward.

I said the UC is the standard amount but my rent is covered. This is a full service area and HB was stopped on the switchover from ESA to UC.

So my questions:

Given that, in theory, I could withdraw the full amount from the SIPP tomorrow, will I get any PC?

If not (or hardly any) what will be my position re UC?

And if UC stops, considering the SIPP will I be eligible for HB?

Sorry for the complexity, I'll be very grateful if anyone can help reduce all this uncertainty. I'm prepared to live mostly on capital for the next six months if I have to, I'd just like to know!