No we have done Avalon headliners and they are fairly straightforward, sometimes there are straps on the a pillars that you have to figure out how to get out,or look on YouTube to see how. And trying to recall grab handles may have push in clips not screws.

We do a lot of leather refinishing, a lot of newer leather does stain easily, dye transfer from leather belts, blue jeans, bronzing spray on tan, red dye from koolaid, all can soak into some leather. If a mild cleaner like Simple Green diluted or rubbing alcohol doesn’t get the stain out the only fix would be to spray a finish over it to cover the stain.
We do that type work on a daily basis.

You shouldn’t have any issues doing that headliner as airbags are installed under the headliner. Should be able to R&R headliner w/o having to do anything involving the airbags. Really that’s typical for all newer vehicles w side curtain airbags.
We install seat air bags and new covers all the time for body shops. And on occasion when the side curtain airbags have deployed we have Installed the new headliner and those airbags, it’s not that hard to do.
The body shop has to get the SRS lights reset afterwards.

Unplugging the harness on the Chevy pickups SUVs is a real pain, the disconnect is way down below the dash on the LH side, I did it one time, since then I just pull the harness off and either glue or tape it back on after recovering the board.
Some late model Cadillacs have the disconnect under the rear package shelf, you have to pull the rear seats trim and package shelf to access it.
For some reason a lot of folks think that headliners should be cheap,. unlike years ago most of them are not any fun to do anymore, some are very complicated, VW Jetta is one that is tough!

I've worked on a few older Recaro seats but never completely recovered them, nice job on the black ones! Sort of like the old Volvo headrests and some others (Lexus LS) , you have to get access into the seat frame to get the clips out to remove them.

I have a shelf that I drilled holes and glued some dowel rods in, that's where I keep most of my threads.
And definitely tag material so you will know what it is down the road.

I worked on an Audi a few months ago, leather facing, vinyl band.
Check with Coast to Coast Leather, GAHH, Veteran's company, they all carry leather and vinyl.
You may just have to match it up to something else as close as possible, that's what I had to do on the Audi I worked on.

For solvent base I've been using the SEM Colorcoat since 1983, we buy it bulk and mix our own colors. The SEM spray can stuff is junk IMO.
ColorBond solvent in aerosol cans is pretty good stuff, covers much better than the SEM spray cans and the factory colors are spot on.
For leather if it's high end or retail I use some water borne finishes, much more durable and feels better too.

There were some chairs like that at the SEMA show that we went to in 2016, weird for sure!

Just don't steam perforated leather!

I've used headliner listing for years, sometimes it's not the wide enough so I have to make my own, or if I need something more heavy duty.

Probably varies around the country we get at least $250 for an ext cab , they are somewhat of a pain, you have to pull the wiring harness off of the back of the headliner, it's glued on with hot melt glue.
There is a disconnect, way up inside the dash, I only did that ONE time!

Actually the hard wired harness above may have come that way from the factory.
I've run into that on several GM SUVs, in the past year or two.
The first time I assumed that someone had rigged it up but after seeing several more , and noticing how the wiring was very neatly done and so neatly wrapped up with cloth tape I figured something else was up.
So I asked the dealership about it , they told me that apparently the factory had some issue the disconnects on some models for a few years (?) and they just hardwired the airbag wires.
To do the work I cut the leads, did the upholstery work, then resoldered and shrink wrapped the wires like before.

I've used Jiffy Steamers for years, they work well and last a very long time.