Cintique armchair repair

I'm attempting to repair my MILs cintique armchair.
Several dowels have broken, which is easy enough to to fix, but I'm a bit stumped on the best way to reassemble.
A couple of pics for context.
The chair is sprung with a Web of springs
. Attachment 527701

Overall view
Attachment 527702

Problem area
Attachment 527703

I didnt realise the arm was screwed to the leg, so I wrestled it off.
If I screw it back on, I'm left with dowels in 2 directions to fit, simultaneously, and there may not be enough flex to do that.
I think the original assembly used this bolt at the back of the arm, now covered with a plug.
Attachment 527704

But if i remove the plug I doubt I can get any sort of matching finish to replace it.

I'd also like to reupholster the arms, but while one side is currently accessible, the other isn't without similar disassembly.
I i will probably just cut away what I can and staple the new cover on.

Am I missing something obvious?

Update.. Yes, I did miss something obvious for the upholstery at least. The arm padding is only held by 2 screws not 3, both easily accessible.. 😳

And of course I can't just screw the arm on anyway as the thread is stripped.
I can either plug and drill, or put some epoxy in the hole and push.
I'm thinking that is probably the only option.

Russ

Plug & drill would keep it closer to original and, to my mind, be the better option.

I realise I didnt explain my main issue well.
If I screw the arm support back on, I'm not sure I will be able to spread the sides apart enough to refit the rails. I have to screw it on first as the screw is fixed to the arm, then attach the rails..if i use epoxy, i can (try to) assemble everything at once.

Although I have realised the rear joints, which are bolted do have a little more movement than expected.

The springs then tension everything up. If I can get them back on...