There is good information on the gg wiki, but a summary if you want to fight as little as possible and don't care about optimizing income beyond what can pay for end game fleets:
- Join PL after raiding their cap for pristine forge = 5% gross income hit w/o fighting blockade. Doing this also blocks hegemony permanently unless you leave PL.
- You can also block hegemony permanently by only using AI cores in size 3 planets or none.
- Block immigration for LC, which requires you to not be at war with them when you get luddic majority, a quick trip to one of their planets, and nothing else.
- Give LP a planet killer. You have to be strong enough to beat the damaged nexus and the fleet guarding it, unless you first run a hegemony commission to get the planet killer (and get it while just exploring). Then you don't need any real combat strength. Their interest is similar to hegemony but even more lax; they tolerate colony items and even some AI usage if it isn't admin.
- Negotiating with Kanta is strongly incentivized; pirate fleets aren't exactly strong, we've been crushing them for a long time before colonies most likely, so it's not some challenge you look forward to doing. You get the best reward for negotiating, which you can do immediately. At least with LC negotiation, you're giving something up to avoid the crisis (which fighting improves instead of removes).
- TT throws some mercenary fleets your way guaranteed. If you disrupt their industries ASAP after their meter starts, this is the extent of their crisis. I guess be strong enough to handle 200k bounties, or stealthy + fast enough to bait them into a station.
- SD never attacks you unless you make fuel. You can raid them just like PL, which ends their crisis instantly. It does forego the bonus fuel income though.
Hence, if you can put together a strong enough marine force to steal colony items from the factions, you can end every crisis w/o fighting a fleet except TT. TT mercenaries will attack you twice regardless, but they are much weaker than full on crisis fleets, and that's the only fleet on fleet combat require to end all crises...