Just a rough cut says about 20,000+ gallons so the pump Ted recommends, 1 HP 2 speed, would be just fine. Even with that I'd go with a 300# filter instead of the 200. You can't go too big on a filter but you can go too small. I personally would stay away from main drains but that's just my quirk because of the accessability to fix it if something goes wrong. However, manually vacuuming an AG pool is generally harder than an inground because of the reach and not being able to stand on a deck all around, unless you're planning on on a deck. Without a deck a main drain could really help.
Just my nickels worth. Hope the build goes well and you enjoy your new pool.
Al