What kind of stabilizers can I use when making souffles, Japanese cheesecake or egg beaten products?
For non-culinary reasons, I would offer substitutions to gelatin;


As for a powerful stabilizer akin to gelatin but that doesn't precisely gel (go to pectin for that), when you are heating the food I have found agar to be a pretty effective stabilizer in vegan quiche that rely on a silken tofu base.
I have used it to stabilize cheesecakes, pudding pies, and puree
based pies and been pleased each time.
As for a middling stabilizer/thickener, i.e. if you don't want to
veer nearer to the gelatin edge, you can try tapioca flour; per
Isa Chandra Moskovitz, "[sometimes tapioca flour can be used]
interchangeably with corn-starch in recipes, but we feel it does have
a different kind of cooked texture (thicker, gooier)."[VPITS
p.7]