Sorry, I didn't see your previous post... I think the answer is yes, you need to take the M/C off to take the body off. You have to take the M/C push rod out to take the body off and I believe the only way you can take it out is to detach it from the M/C. My memory is a little fuzzy there but I think that's right. BTW, if you're planning on keeping your M/C I would recommend White Post Restorations (
https://whitepost.com/#hometop) to rebuild it. They seem to be able to rebuild any hydraulic bit from any car and they line the bore with copper (or is it brass?) so the bore should never need attention again.
You certainly have your work cut out for you! I don't think I remember critters taking up lodging in the 'T' section before!
I've probably already suggested to make more access to the steering u-joint (but you'll just have to live with that. Wait till you start talking about your dash and you'll get tired of me reminding you to finish both sides and all the edges to keep moisture out!). If you can find someone with a flaring die punch (I think I've heard them called a chassis punch). Eastwood has them but you might want to find someone who has one already. Alternatively, you could probably fabricate something.