I think this roughly makes sense? 

A crux here would be whether you think there are enough people and funding going to the most important opportunities/directions of work. 
OP has a lot of money, but they are not funding everything. If you think they cover almost everything important then that is there is a stronger case for direct work (e.g. try to get a grant from them) 

You should also think about how confident you are that you can spend your own money effectively. Are you planning to choose projects to fund yourself? Will you defer to LTFF? How much do you trust the judgement of their evaluators compared to yours in knowing what's important?

You should likely explore high-absorbancy career paths (e.g., fieldbuilding, comms) as well, as the ones you refer to in the post seem to be low-absorbancy.

I think that is a reasonable path; SWE/ML will give you a good foundation anyways  in early career if you want to switch to AI safety later as you build experience. Additionally, something in security is a good idea as well.