This looks like a variegated ficus benjamina. They respond well to bonsai culture although they are just a bit finicky with changes in temperature, etc. They seem easy to graft, are extremely easy to air layer, and it should be a fun tree to learn some techniques on. If you cut the branches way back, you should see back budding, although you may not find it exactly where you want.
My own first houseplant that I turned into bonsai was a benjamina. It had five tall spindly trunks that my dad had tied up to a broomstick to keep them from falling over. I airlayered about seven trees successfully from that one, and learned a great deal from it.
Good luck to you.