A motor at appr 50Watt would suit. I would have chosen a small brushless that suits the tiny nose of the glider and a folding prop is a must.
I would also have used LiPo and since you just need 2 servoes onboard use the BEC from the speedcontroller instead of a separate RX-battery. 2S or 3S LiPo of 700mAh is what I think of.
Of course it will fly using a brushed motor and for example KAN950 NiMh batteries. The problem using brushed motors is they often require gear... Both a heavy motor and a noisy and heavy gearbox reduse the performance.
Modified Eppler205 profile gives you a relaxing plane, classic look and really cute I think
