flexible - you'll need to print slowly.
around 20-30mm/s for polyflex or the stiffer flexible pla's
and 5-10mm/s for the flexible tpus.

Also i've found that increasing my extrusion to 120-130% is also a good idea for the tpu's.

Temp wise, pretty much what it says on the reel. Aim for the middle of the temp range initially.

You can have the first layer at 100% and for the all the flexibles I've tried (except polyflex) you don't need a heated bed. For polyflex treat like pla at 50c.

Yeah pet-g prints alittle slower than pla and a little hotter.