That is awesome progress, I'm so excited to see a project like this! I definitely want to do my own rusty-1911 project, I just have to find one now
I'm a little worried for you on the plunger tube... Have you pulled the plungers/spring out? If so, a fine punch might work those out, I can't imagine there is enough mass left on them to not just fall out with a little tap.
I would suspect you could find someone with a good mill (or even a drill press if you're brave), and carefully re-drill the tube. A good vice and trial/error could make it pretty easy.
The 1911 blueprints are here:
http://www.m1911.org/technic.htm
So, edited to add: I found the page on the first link (full blueprints) of the plunger tube. See page 45 of 56.
Don't take this as gospel, but it looks like the smaller takedown side is .091 diameter +.004, the other side is .109 diameter +.003. (The + is tolerance I suspect?!).
.091 is about 1/2 way between a #43 and a #42 drill bit, with the #42 being inside the tolerance, but fairly large (#42 is .0935).
.109 is almost perfectly a 7/64" drill bit (7/64" is actually .109375)!