Regarding the lithium, once the coenzymes are at optimal levels, will I need to continue taking this long term, or is it just while improving the deficiency?

It really depends on how you react when you take it and how you feel while taking it. If it seems to help you and your mental health improve, then I would just keep taking it.

But it’s also possible your lithium levels are simply depleted due to chronic stress. And then once you supplement for a while, and you reduce your stress, then your lithium levels will be topped up. And then you won't need to supplement anymore. 

But in the meantime, I would just take it and see how you feel about it. And then keep taking it if it helps