Welcome aboard!
Looks like you have things well in hand at this point & have done a fair amount of trolling for info. Well done!
You should also consider converting the drum brakes to disks. It can be done for little money if you grab some of the key parts from a bone yard, & will offer you more trouble-free motoring and potentially better braking performance.
The P0401 may go away after you do the TB cleaning so the expense of an EGR valve might be avoided. Those passages behind the TB gasket get clogged up pretty bad.

When you're done, I'm sure you'll learn to love your car. Enjoy!!
JimR