OK, I like magdrive pumps. You will need to have a small one.
That looks like more than 2 feet of head. Measure the bottom of the 10 gallon to the top of the main display. this will tell you how much head.
Then you will need to find a pump that will do the GPH you want with the head you measured.
I didn't look up the magdrive spects, but I think a magdrive 2 is 250 GPH at 0 head. At your head (i'm guessing) of 3.5'/4' it would be (guessing again) 100 GPH. That is a 5x turnover in a hour. That with a small powerhead or 2 would be pretty good.
You will need to measure and do reaseach on some pumps for the GPH you want. Generally speaking 10x turn over for a reef. That includes PH's.
I made my own overflow out of PVC. Unfortunatly I don't have a Pic. I could draw something up for you if you want, let me know.
As for the the refuge, all I did is make a divider out of plexi-glass and used aquarium sealant to glue it in. 2/3 refuge, 1/3 sump. I will also post a pic.
The left is the refuge. The overflow pipe tee's off. One goes back to the sump and one to the refuge. the right is the sump.
HTH