Fabric coverings are often used for Cubs and other "scale" planes that had fabric covering. You can find fabrics that come in standard Cub yellow, or use the type you need to paint yourself.

The weight added by the fabric won't be an issue on a plane like the 60 size Cub, it has plenty of wing area to carry the slight weight penalty.

You can mount the four stroke inverted if you wish, and an on board glow driver will certainly reduce the small potential for starting and idling problems. Many also let the cylinder stick out the side of the cowl, and then match it as closely as possible on the other side. After all, Cubs had cylinder heads sticking out the sides of the cowl anyway. Or, you could buy a nice 4 stroke twin to fit the cowl and be really scale.

Standard servos, like the Futaba 3003, or the 3004 ball bearing servos will be fine for the 60 size Cub. You won't need high torque as it's not a high speed, aerobatic plane. If you were asking about a 60 size CAP or Extra my answer might be different.

Good luck, and follow that plan of starting with a trainer, just get an instructor too.

Welcome to RCU and the terrific world of RC flying. Not much else out there compares to the enjoyment you'll get from it.
Dennis-