You obviously have no idea what you are talking about.
If SA:MP server is optimized, it won't use a lot of RAM.
As long as he is not receiving enormous traffic, apache2 and teamspeak should be fine too.
When you have a full teamspeak server running and server, you may want to have free ram for server updates, and since he is going to use a mysql, he will need about 200mb ram for mysql server.