That's wonderful that you are able to do so much still (working, biking etc.)
Did you take anytime off when you had your accident? I ask because the twitching you experience especially before bed is something I went through and still do when I'm exhausted. My doctor told me it was normal for someone who had a brain injury, but that it was a sign my nervous system was still healing and that I needed to rest as much as possible. Is there anyway you can cut back somewhere and get more rest?
Dizzieness is something I dealt with a lot when I had my accident. I went to vestibular rehab to work on fixing this problem. Its like PT for your balance systems. It really made a huge difference for me. Also, have you had your eyes checked? Many people develop vision issues after an accident like yours. For example your eyes may be sending images to your brain that are hard to match up because your eyes at working together. This could also explain the dizziness.
Brain fog.... yeahhhhh. This one still gets me. I see a rehab doctor who has added medication to help me combat this, (ADHD drug), but it only works when the pill is in my system, so I have to do most of my thinking during this time period, (ex school work, decision making, etc) while I'm on it.
However, most importantly what you are describing is normal. They all will improve if you find more time for your brain to rest