Most submersible utility pumps work well for this. What wefound was don't restrict the blumbing, If its an 1.5 opening, use 1.5 hose to pump out, not a garden hose.
If you aren't sure what type or where to get a pump
Maybe you're not ready.
Unless your trying to look like you're building a rug plant well then ask Better questions
I would say a pump heavier than a standard sump pump. You're going to have lots of dirt and grit to pump out of the pit, so I would go with a cast iron pump....possibly a trash pump. If not, you will be replacing it often.