First of all, the blade will bow up like a bananna when you are forging the bevels in. You are stretching the steel progressively more as you forge to the edge and not moving the steel in the spine at all. It's just going to happen and is frequently seen on first attempts. To get around that you need to heat the blade just ahead of where the curve starts, I have better results laying the spine against the face of the anvil, and tapping the blade straight. The reason you don't heat the whole blade is that you want to keep the steel that has not curves as mush straight. If the curving is real bak you might have to work in sections until you have it the way that you want it.
You can use a hammer to do this but you can also make yourself what is called a thwacker (at least some of us call it a thwacker) out of wood. Some make them to look like a wooden club, which is basically what they are. I couldn't find a piece of wood stock that I wanted to carve down so I got a rough turned blank of apple wood about 4" in diameter and 5" long made for turning a vase from, drilled a hole in one end and glued a 3/4" wood dowel in. Basically it looks like a mall. The advantage to it is that it will have enough weight to move the steel but the wood will give and not dent it so much. It also comes in handy for straightening blades. I got the blank from a wood supplier who sells such things to wood turners.
As far as forging in the bevels, the way that you describe is how I do it and don't seem to have problems. Another was is to work the edges at and parallel to the edge of the anvil and at the same time raise the spine of the blade slightly off the surface of the anvil. There is no one way of doing many things in forging, just the way that it works for you.
Doug