The meat is somewhat bland, but it's exactly how you'd expect. You could do all kinds of things with this, it's like a platform. They say lamb is great.
Could be. Consider pre-cooking meat to some extent to remove as much oil as possible beforehand. That's a downside of using raw meat in these, the oil has nowhere to go.
This is the recipe I followed: https://petersfoodadventures.com/2018/10/19/chebureki/
I hate rolling dough, but this is really easy to work with if maybe a bit strong, but not sticky like cookie or pie dough. Make sure it's real thin.
The oil needs to be just hot enough to fry, you want it to cook low and slow. Keep the meat in the pocket pressed thin and even. It takes about 1:45 to 2:00 per side to cook. This recipe uses a ton of onion, maybe cut it back about 50% and see how it goes.