Last Indian

There are many different types, but a good one, like this one from Summit will give you what you need. It has a check valve that allows for vacuum to be stored. So when you are pulling 14 or 15” of vacuum the canister stores that. So even if you need to apply your brakes in a low vacuum condition you still have 14 or 15” of vacuum to apply to the brakes. 14 to 15” of vacuum is more than enough to operate most all vacuum assisted parts. Brakes, air, etc.
https://www.summitracing.com/parts/cvs-vpr700#overview

The irid stands for iridium not iridescent. Gm used iridium as the metallic in some of the metallic paint colors. It reflects differently than a typical metallic flake does. To a degree it fluoresce as opposed to metallic reflecting. 

That is just a fill port, not a dipstick check port. These units work like a rear axle car.  You need the car jacked up. Underneath there is a drain/level check plug. There is a procedure to go through, car needs to be at temperature. Run the tranny through the gears, put it back in park pull the plug. If the oil level is at the bottom of the plug hole you’re good, if not add oil slowly, a little at a time. When oil starts to drip out of the hole, stop. Reinstall the plug.
p.s. When jacked up the car needs to be level.

If it looks like this yes!

then google RPO Pontiac codes

Those are excellent jack stands! More than sufficient for even a 4000 lb car like my Lacrosse’s. The only thing I get concerned about with all of those types of jack stands are the top footprint. It’s conducive if there is a channel to place in the V groove of the top part of the jack or a good flat portion of frame, which today most cars don’t have! 
So I made my own many years age out of 3” pipe and pipe flanges! Very very stable & very strong! Still what you have is good!