Hi!
Any other nifty strategies with trade?
Don't build your econ on trading. Compared to income one could get from trade in GC-1 it's now over-nerfed. Trade routes also have a bit too many events that make them go poof. So you better use trade just as a diplomatic tool that also makes some money, and forget econ SBs.
OFC there's also the exception: if you have only a few planets, trade can make a big part of your econ.
Will those relation benefits then prevent the beginnings of the galaxy-wide wartime?
Not necessary. Trading just gives one or two "pluses" to relations. If there are too many "minuses", war can still break out, but likely lately than without trade.
When you give a freighter, what planet is then chosen as the "owner" for that freighter
IIRC the homeworld.
BR, Iztok