Don't worry about the forearm. I have never gotten it all to line up perfectly. I not even sure perfect is possible as the wood moves and twists on you. The orginials didn't have stuff perfect. They just smoothed everything out and made sure stuff looked right relative to each other. If you start measuring them, you will quickly learn that not a lot of measurement and planning when into those things. They just put the gun together the way that looked right to them. If you get it too perfect, it looks machine made.
You do need to be careful when inletting not to twist the barrel in the inlet when you hammer it in for each fitting. Also, inletting the barrel with the breech plug in place can help, but you may still end up the stock and barrel out of square at the muzzle. You just get it as close as you can. The general rule of thumb is that EVERYTHING on the gun is relative to the barrel. That is why you inlet it first. So, it you get the barrel in the stock crooked, then everything else should be crooked to match. When you are done and everything is crooked together, it will all look fine.
As to your situation now, you might be able to square up your lock panels with the barrel. If not, the only way to fix the thing is start over with a new piece of wood. I have done that a couple of times when I just didn't like the way things were going. For me, it is usually driliing the ramrod hole. For some pieces of wood, I think they just don't want to be a gun stock(I have one gun that just doesn't seem to want to be), but usually, it is me being in too big of an hurry. At 70 hours, you really don't have that much in the gun and presumably, a lot of that was prep work on your mounts which you won't loose. I had around 300 hours in the last gun I finished. I am sure there are others on this board that have put way more than that in a gun. Some pictures of what you have may help with recommendations.