Hey thanks for the feedback,
1. After getting hit, you only have 0.5s of invincibility. I don't remember where but I believe Team Cherry mentioned that they were gonna make Silksong more fast-paced, i.e. you can lose health really quickly, but can also regain health just as fast. But I have just added a difficulty option, which has a longer invincibility. Also I believe there is knock back when you get hit but after the freeze frame.
2. I'll see what I can do about making Stuart's jump more telegraphed.
3. Honestly, I noticed that Hornet is really floaty too. However, I'm not too sure how to fix that.