I am running
KStars 3.4.2 (2020-04-13 build),
Ekos (not sure how to find the version in Ekos, but I just installed a couple days ago),
indi_lx200fs2 v.2.2 interface 5.

My FS-2 controller is running 1.21.

I read on a previous thread that the mount doesn't receive a "stop" command after parking, and this looks consistent with both my debug logs and a quick peek at LX200FS2::Park().

My questions are these:
1) Is the current driver written only to support a newer version of my firmware? My understanding is that 1.26 is out, and I'm in the process of seeing if I can get a new EEPROM shipped.
2) Is it possible for me to use an older version of the driver that works with v1.21 firmware?
3) I also found a thread that showed the LX200 commands to use to stop the mount -- I'm happy to write the code and submit a PR, but I want to make sure that I don't stomp any one else's config, and I've not edited an INDI driver before.

Perhaps you are seeing the same behavior as described and discussed in this thread?

indilib.org/forum/ekos/7010-ekos-enters-...equest-for-data.html

I don't believe so; I read that thread, and it seems to be about meridian flip being bad mojo.
While I am happy to believe that MF has messed up this party, I have a pretty succinct 22k log that shows a park request, a slew of about 30º to the park position, no MF required (my park position is 90º Az / 0º Alt, CW down OTA pointing at the East horizon), and the status changing to "parked" with the mount's position stable at the target Alt/Az.

...

except the motors never turned off.

There's no indication in the logs that any "stop" command was sent to the mount anywhere near the status update to Parked.

In the thread I linked, above, there's a suggestion that the INDI FS2 driver only works with more recent versions of the FS2 firmware.
I'd be just as happy to have a checkbox that says "Send stop command after parked", which can be checked by people who have an older version of the mount hardware, and who need to either use an older INDI driver that works with older firmware (was there ever a version that worked with v1.21?), or a mod to the current version.

I am wondering if other FS2 users have ever gotten Parking to work, and if so, how did they do it? This appears to be implemented differently for almost every LX200-flavored driver.

I have attempted to make FS-2 park properly by turning off the motors when parked (set rate to CENTERING, move East).

This works great, and the mount parks and unparks, and slews just fine...

...until I completely stop Ekos and restart it.
At this point, Ekos turns on tracking, but doesn't unpark the mount -- this leaves the mount in a weird state where it can't be slewed.

Can someone help me to understand how to maintain this behavior across reboots?

I also noticed that @SevenW is trying the same thing under LX200 Classic. His method is to set Alignment to :"Land". His code looks similar, but he's having a problem at unpark as well.

Is either of these methods the correct way to do this? My goal is to be able to shut down and park the mount at the end of a session, and have it sit with motors off until I get back. I have submitted a PR from my fork, so that we can discuss the code before it gets merged.