In this one, it applies to Mario & Luigi only, the Penguin Suit has a an incorrectly vertical hitbox value of 48, but it should be 54 (for Mario) and 60 (for Luigi) like their other big forms.
2- Spin Jump (Fixed)
The Spin jump itself is not a bug, but yes how it is triggered, while you're falling (normal jump) and holding the spin jump button, the player will simulate the spin jump in a frame or two, it's more noticeable when you have a Fire Flower (or Ice Flower, Hammer Suit, Penguin Suit) or on a Flip Block
3- Tanooki/Raccoon Block Hit from Above
If you time it correctly, you can hit blocks by tail swiping from above
4- Hit in midair bug (Fixed)
This is something that definitely shouldn't happen, upon being hit by an enemy in midair while your jump is starting, you lose your momentum even if you're holding the jump key.
