2000 9-5 Aero

I've finally returned to the fold, and boy does it feel nice!

On Saturday I flew down to California and bought this beauty - a 2000 9-5 Aero... with a manual and 146k miles. It's been a California car all its life, and has ventilated seats, the Harman audio package - it's great.
Took it for a test drive and heard no issues before or after, no engine codes. I found a body shop down the street who let me use their lift, and only found two small oil leaks, which I was expecting. Everything else looked pretty nice.

Re-learning to drive a manual has been interesting, and I can't tell whether it's my lack of skill or that the transmission/engine mounts are all shot, but things seem to bounce around more than I'd expect. Other than that, no major mechanical issues that I can find, and it was super smooth on the 600 mile ride home, straight through.

Here's the short (hah) list of to-do's, some of which are preventive:

Replace the hood and trunk lid support struts
Replace the driver seat cushion - not nearly enough cushion right now for the drive I just took
Change the oil - no service records, but there's a sticker on the window that suggests a change at 150k
Flush the brake system with new fluid
Flush the coolant - it looks like dirty water right now, but at least smells like coolant
Side engine mounts, and lower transmission mount - I'd like to avoid the rear engine mount if I can
Replace rusty lug bolts - rust scares me and they look like garbage
Replace fuel filter - no service records, remember...
Check serpentine belt and replace if necessary

Beyond that, there are small things to do, like replacing the emblems and touching up a few scratches under the rear bumper. I also really need to swap the wheels for some that aren't ultra-retro.

I've got some questions for you knowledgeable folks, if you don't mind...

My previous car was a Mercedes, and I've still got a gallon of their blue coolant - I've read in one or two places that this was the correct coolant for this year (G-48). Can anyone confirm this?
Do I really need to buy Pentosin CHF11S for the power steering? Seems a little expensive.
Will black rubber floor mats look ridiculous in a tan interior? I can't find the rubber tans for sale anywhere.