ATF Drain and Fill advice?

Drive the car onto a pair of low-slung rhino ramps. That's about as stable as you can get it. Use your floor jack to jack up the rear to level the car. You don't have to bother with jack stands, since your at the front of the car on solid ramps.
Just make sure you put in as much as you drain from the transaxle, as a double-check, in case your not level.

 

See transaxle fluid change in my signature, some info. (On a phone turn it landscape to see signatures)

regarding stability while raising/levelling, my drill:

1. chock rear wheels fore and aft, then release parking brake.

2. raise front via proscribed front jacking point.

3. place jack stands* and settle car onto them.

4. raise rear via proscribed rear jacking point. Aim to have it slightly higher than front, initially.

5. place jack stands* and settle car onto them.

6. Verify you’ve got solid bearing at all four corners: if slab is not sufficiently planar, as evidenced by a loose jackstands, raise, shim under jackstand and retry.

7. Bring car back down in reverse order.

* see oil change link in signature for my preferred jack stand placement.