Yes it will keep cats out if you zip the zipper, tighten the drawstring and tuck the bottom under the crib/playpen or anything heavy. However this is not designed specially for cats.

It looks the best for cribs with flat tops. But will be functional on convertible cribs if the height of the net (43'') is enough to cover your crib.

The playpen net (41 by 28 inches) should fit a mini crib

Watch the video demonstration here https://youtu.be/od8yIF_yO7I

The top of the canopy is made from solid fabric and the net covers the entire bed - so yes this will cover the space above the bed if that's your question.

Yes, you can remove the top "skirt" with a pair of scissors without cutting the stitching open. Or you can fold them on top of the canopy so you don't see them from the outside.

Yes it will fit a four post bed by putting the net directly outside of the posts or by tying the ribbon ties on the post. The net has ribbon ties both inside and outside.

It has three openings on three sides besides the twin size canopy has only one opening on the long side

It's white. The pictures may appear other color due to the lighting.

There’s no pesticide in the net. The smell is normal from the nylon fabric and should go away within several days of use or after wash, similar to new clothes.

That's totally doable but not available at this moment. We do have canopies without hearts for regular beds though.