OHS can't really be a max effort movement since you really can't load it very high. I would stick with trapbar deadlifts and front squats until you can start doing deadlifts and back squats. Obviously you can do the TBDL from deficit or from blocks if your really want, but again, be careful with your back. Don't do anything too extreme too soon. Because of your injury and the fact that different lifts work better for different people, it's hard to say what you should do. As long as you get stronger, who cares?
You don't necessarily have to save bands and chains for later. Just don't think they are the end all be all of strength training. You don't NEED them, but the will give you a different type of resistance than you get from straight weight. Bands and chains basically give you more options as far as lift variations go.
You can do DE work if you really want to. It can only help, especially if you are weak at the bottom of the lifts. Again, different people respond differently to certain stimuli than others. Many people get strong without necessarily training speed too much. Don't over think it. If you get stronger, no matter what you are doing, then keep doing it.