Will this fit my 20-inch folding e-bike?

It fits 20-inch rims with ETRTO 406 that accept 3.00 to 4.00 wide tires. Check frame and fender clearance before buying, since the 4.00 version is much wider.

Can I set it up tubeless?

No. Kenda lists it as not tubeless ready, so it should be run with an inner tube. A 20 x 3.50-4.00 Schrader tube is suggested.

Is it approved for e-bikes?

No, it has no e-bike certification. That matters most for faster or heavier e-bikes where motor torque and weight put more stress on the tire.

How does the 20x3.00 compare with the 20x4.00?

The 3.00 is lighter at about 1100 g and fits narrower frames; the 4.00 is about 1400 g and gives more cushion and float. Both use the same slick K1032 tread.

Is a slick tread good for city riding?

Yes on pavement and smooth paths, where it rolls efficiently and quietly. It gives up grip on loose dirt, gravel and wet surfaces compared with a knobby tire.