Unfortunately, we do not have the necessary experience to answer your question. Therefore, your inquiry has been forwarded to our Community so someone with more knowledge can answer.

Yes, they are rubberised.

is designed for children from 2 to 5 years (up to 22 kg) and can be fitted to most modern mountain bikes with front suspension. However, this seat is not suitable for electric bikes. For e-bikes, the manufacturer recommends the Shotgun Pro Combo seat, which has been specially developed for use with e-mountain bikes. This seat is mounted without frame contact and is equipped with an adjustable leg width to fit wider down tubes of e-bikes.

I don't know. But I don't think so. I would go for the newer model... as the frame must be really thin for this version.

What is the exact model of the electric bicycle in question? We can ask the product manager. :)