Great little forge. Well made and thought out.
You are right about your anvil, it would wobble a lot. If the angle iron is all you have at present try making your frame into a sawing horse so it is at least more stable. That arrangement will buy you some time while you find a good chunk of iron for a more solid arrangement.
While forging try not to go to bright white, a good orange/yellow will do for mild steel.
Cheers