Hmm, I did reduce min speed to 1 and set max to 10 in my 1.19 files. I forgot to do that since putting 1.27. Mainly did this because of the big ship speeds.
You know, I haven't noticed the fighter thing. I, once upon a time, had planetary fighters, {launch from planet only}, but I think the AI would load them on carriers and then not know what to do with them. So I removed them. I tried to use troops to board too. Nada. So many things I wish the darn thing would do.
AS to your other questions, I was able to play a few days Last week and week end,

, with 1.27. Since then have not had any time.
I will check some more this week end Sinapus. I was going to clean out everything and just run the Modpack 1.60 and make some minor PD changes in line with GE's work.
I haven't messed with the AI files much. I generally try to Mod around them since I don't understand them that well nor feel I have the time to get into them right now.
Our problem would be solved if we can get some of them non-working abilities working.
Sorry this didn't help ya. If you find a solution I would love to know about it.