Temperate is good for bears, usually never have to worry about temp.
Use any veggie for food as it gives the most food and lasts the longest. I would stuff mine till 4 stacks of celery then just leave em be, that will be enough to 10%. (At 10% they eat from feeding troughs). IIRC 1 stack lasts about 45 min, so you are able to wander off and do some other stuff.
Most of the time youll get 1 cub. But you can get triplets and twins too. (IIRC id get maybe 4 sets of twins with 50 bears poping per run, but rng is rng)
Dont feel bad if your 1st ones go, youll quickly get to the point of letting half or more of a liter die bc of crap stats. (At my "prime" Id pop 50-75 bears and keep 3 or 4 on a good day)
Tigers our company was breeding in tropics but I think you had to heat em at night. There might be better biome but honestly not sure.
Just have lots of meat ready, you will have to baby sit these guys. Dont forget to restack meat in troughs every so often as itll let stacks last a little longer than having em spread out. (Ie 25 stacks will rot 25 meat per decay, but if you can restack em to 13, only 13 stacks are exposed, so you lose 13 meat per decay instead of 25)