From: Los Angeles
3) how effective they can be if there are no U.S. forces on the ground working with them, but just Kurds and other allied or semi-allied forces.
If you mean if there are no U.S. ground crews, then clearly the answer is they cannot be effective. This pretty much rules out using them in Syria. If you mean, as I imagine you do, that you will need Kurds or other locals to call in targeting information, then my guess is that A-10's could work fairly well, especially if we could fly drones over the area to confirm the reports from the ground.
Civil war? What does that mean? Is there any foreign war? Isn't every war fought between men, between brothers?