Very poignant question - attack aircraft are currently undergoing some interesting developments in this very area. No definite word on ground units, but most likely not in the first release.
Yes, this has been fixed in the new editor.
Unfortunately, no. Valery had described the problem on the Russian forum as not so much in the editor, but the game/graphics engine, which is why we are likely to see this much requested feature implemented only in the new engine.
Currently, the standard runway or parking starts are the only options available.
As the ME and AI are being finalized, we will be in a better position to provide detailed descriptions of their features, as we did with radio systems modeling. I've already started drafting some of these up, but we still have some development time ahead, so I don't expect to be able to post them until at least a few weeks down the line. For now, enjoy the holidays and the presents they may bring... ;)