The vanilla AI is pretty weak on the production side, though it has gotten better. If you want smarter production AI, you can use the Expert AI mod.
I guess I’ve played enough games that I know roughly what to expect. I do find it helpful to look on the details tab of the diplomatic menu to see estimates for divisions, aircraft count, mil factories, etc.
I think they will, but you can adjust how “brave” they are. If you want to keep them out of the fight, it might be better to move them further away from British bases (and have fighter on air superiority over the port, plus AA at the port).
I haven’t played Italy, but generally you want to fight your naval battles under “green air”. If you can get enough fighters on air superiority in the sea zone where you are fighting, their carriers will be largely neutralised ( I believe air superiority still suppresses CV aircraft?). If you can take out their fleet, supplying North Africa will be a lot easier.
If you find one, let me know! I feel this is one area where I was disappointed in the latest naval expansion. Everyone was begging for summarised results (especially for convoy raiding).