Any tips for using these on cabinets or drawers that have pullout drawers above them?

I attached mine sideways so it doesn’t affect the other drawers.

what is preventing the child from jamming their fingers once they pull open the drawer to the small opening?

This safety lock is ineffective. However the child’s finger could get caught. You can choice vmaisi magnetic cabinet locks that have not small gap.

Is it easy to remove? Will it stick the painting of the furniture?

Yes they remove clean with alcohol. You need to be careful taking them off, to not peel off any part of your cabinet.

for cabinets, does this open enough for a cat to slip in? no babies, just a curious kitty!

No. It gives you about a half inch of a gap before you have to push the lock open.

Drawers of my dresser does not even close properly. How to solve the issue?

For inset drawers, the included tool aids in placing the catch deep enough to allow the drawer to close. Most of the dresser drawers required to mount the lock sideways (it still functions!). The included inset ruler tool works well to solve this.