What paint should I use on a concrete statue?
Sealing the concrete is the crucial step. I'd be using two coats of external plastic primer. You can buy primers with more than usual grip, but they cost twice as much (worth it). Then I would paint with a paving paint for extra durability. You might be able able to buy sample pots of enough paint for the whole job.

At some stage someone is going to have scrub it clean of dried bird droppings or even high-pressure wash it, so your paint will need to withstand this. 

If children are going to clamber over it, or people are touching it as they walk past, I'd consider a final clear coat of a slate/concrete sealer to prolong the life of the paint. 

I'd also give the new owner you left over paint or at least the color formula so they can touch up if they need/want to, with details of the products you used for each coat.