Getting started....

I introduced myself on the forum and the introductory yesterday. Excuse me because sometimes things sound a little weird because I use voice command on my phone but I try to correct.. while new to this car forum I've been on a different brand car forum for many years so I'm thankful and appreciative of any advice and will reciprocate when I can and give results of my advice...
Some some of my fondest memories of driving or in my 93 trans am. I've had three others that were older styles. I just purchased a 95 with a 6 speed...
It was a flip car for the guy that I bought it from but I did a Carfax and it does have three previous owners with 75,000 miles.. new paint new rims and tires.. I'm absolutely sure all the rubber has been replaced around the window seals it's just too nice...
On to the mechanicals that's my thing..
So I was told the oil was changed so I'll check that. I trailed it 2 hours last night to my friends storage unit. He owns the place. He also has a car lift that will get the car about for feet off the ground.. this next Tuesday or Wednesday we're going to put it on the lift and I want to start by taking the rear diff cover off replacing it with new fluid and reseal it as it's leaking. While I'm under there I want to change the transmission fluid I guess it's ATF on the stick shift...
The previous owner said he did look that up and said it's the good positive rear end? Not sure what kind of fluid to use there or how much?..
As of right now the low coolant light is on and I'm going to try and pull that sending unit out and clean it or just replace it likely as I've read a little bit about that... The fans seem to kick on almost immediately... Of course for the very first time and it didn't happen on my two test drives of course LOL it was idling a little bit erratically last night when I pulled the top trailer?..
I really want to tackle the spark plugs which I know are a complete nightmare for a couple of them but that's fine. On my last one I took it to the dealership at 97,000 miles and they told me it had 100,000 mi plugs on it and didn't replace them, I nearly lost it... I'm not sure what plugs make these cars happiest if there is a certain one that does?..
Didn't notice any oil leaks.
Once I get all the mechanicals up to snuff I'll work on the small cosmetic things.. the rear hatch struts, the antenna makes the noise like it wants to come up but it doesn't for the radio. The driver side rear tail lens has some significant cracks in it I'd like to replace it. The headliner is starting to peel away on the passenger side and this is the tea top by the way. For a couple hundred bucks probably just replace it..
When I hit the electric trunk button inside it didn't work. Have to use the key.. the driver side unlock button is pushed in and I'll need to get something there like the whole new plastic holder or something, that still needs investigation.. I need key fobs and maybe a second key.. it has a complete alarm system that I have no idea how it works... The previous owner just pulled the fuse..
So for the next few days I'm just going to gather parts and fluids and hopefully get some feedback here...
Thank you for everybody's wisdom advice and experience...