I am slotted for reclass school in the Army reserve, but the VA just put me at 70% service connected. Can I still reclass? What can I expect?

The VA rating percentage has nothing to do with your Army Reserve, other than completing VA Form 21-8951 annually. Many elect to waive the 63 drill days worth of VA compensation and take the drill pay.
You have no profile, and I wouldn't volunteer to seek one. Of course, if you believe any of those conditions interfere with your ability to complete your duties, you should research your options before raising the issue with anyone.

I think that would be tricky, based on my previous experience.

For some conditions a letter from a civilian Doctor stating the condition or illness “ is more likely than not a result of “ can serve as a Nexus. Some conditions or illness will not become apparent until years after your service has ended. And even if a claim is denied there are appeal options now available. It may not be easy and the fight long but staying in the fight is the right thing to do for your and your family. I know a lot of younger and still serving vets may not feel veterans organizations worthwhile but really that’s where your going to find your SME’s for all things VA. That and your own hard work and research will win the day every time.