Answer 1: The plane you listed isn't a good choice for learning. The problem with scale or scale appearing planes is they are typically not as light or stable as a plane designed to be a trainer. There's a list of trainer planes pinned to the top of this forum. Since you're on a budget, one good choice is the Tower Trainer.
Answer 2: The .40 LA would be ok for a trainer. The .46 LA is only slightly more money, but would give you a bit more power.
Answer 3: The radio should do fine, as long as it's on an aircraft frequency. Is it 72 or 75 mhz?
Answer 4: Standard servos are fine for trainers. In the Futaba line these would be S3003 or S3304. A similar for Hitec would be HS325.

Also remember that you need to factor in the cost of some basic tools, glue, and field tools for fueling and starting your engine. You may have much of these already if you do nitro cars or trucks. You should also plan to join a club for instruction, meaning you should join AMA and the club.

Anyway, the plane purchase can be done quite economically. Good luck. If you've got more questions, or want clarification, ask away, we're here to help.