About Bicycles for a change

I have a Redline Conquest cross bike.

I was using flat bars on the bike but cannot stand them and am changing over to drop bars. This causes me to replace all of the parts that are on the bike since they are really MTB parts. Thee are some things that I need that I don't see able to find anymo

1. A compact 175 crankset that has a 24 mm shaft. Is Shimano 105 a proper replacement for the BB386 bearings?

2. The seat tube is 32.4 mm and I can't find any adapter for the braze-on front derailleur I have for a compact crank. To fit a 31.8 mm it appears that I would have to force it to the point that it would scratch the paint off.. The clamp on front derailleur is a 34.8 or whatever with some nylon adapters. These things are welded to the clamp with time. There must be somewhere that I can get these plastic adapters or has the almost entire switch over to CF bikes killed that market?

This way the bike will double for me as a gravel/cross bike and when my anti-carbon fiber friend visits I can drop the seat to the proper level for him. It is pretty odd that most of my bikes now are what they call Extra-Large or 58 cm. I'm sort of anxious to get the Basso up again and compare the 62 cm ride to the 58.