Edit: I am looking for better Autofocus, FPS, and durability. I would also like to get into full frame, but that is not a necessity. I just want to be able to consistently get action shots where the autofocus can handle fast moving subjects at a close range.
Of your list, I would vote none of them.
With all of those on that list you are making some sort of compromise that will partially defeat the purpose.
On the combos you are using the Sigma 150-600mm C, you are taking a hit in the AF speed due to the slow speed of the lens.
On the combos that don't have stacked sensors, you are loosing one of the things that makes AF work so great on mirrorless ... the ability to keep the subject properly framed).
On the combos that use adapter lenses, you are introducing multiple points of failure (warped mounts, water ingress and so on).
You need to take into account also when talking about FPS not only how many a camera can do but at what cost (a camera that does 20fps in e-shutter but has major rolling shutter is useless), how deep is the buffer, how fast does it clear that buffer (and how expensive are the cards for that body).
If you must stay in the budget, I would rather have a used D500 and a 500mm PF over any of those combos.
If you must have mirrorless in the budget, I would have an Olympus OM-1 and an used 300mm f4 with the 1.4x TC and 2x TCs over any of those combos.
And if you must have one of those combos I would have an R7 and 100-500mm or Z8 with the 150-600mm C and prepare for a lens upgrade in the near future.