Your concrete supplier/mixer will have the ability to offer up some advice. Adding tinted powder is done often but not always as a floor colour. No matter what you do, concrete must cure before much else can be done to the area/region. Each mixture differs but the rule of thumb = 1 day of cure per 1mm thickness (1 inch concrete = 25.4mm = 1 month to cure). The thicker the top coat the longer you have to wait before you do "stuff" to the concrete.

What finish are you using over the concrete? Are you adding a vapour barrier to the current concrete and then pouring over? Garage floors are often poured without moisture barrier because at the time they are built they are not considered "living spaces" and therefore do not recieve the same love and attention that a basement slab/house slab are awarded (ie. they get proper grading/drainage, proper moisture barriers, proper sealing, etc).

Why can't you wait 4-6 weeks for the acid stain/epoxy finish?

Wow, thanks so much for the info. and you are way ahead of me! I had not thought of a vapor barrier, but that makes sense. And I have no idea what kind of finish. I am just starting the process. I am in a rush to get it done by the end of February to rent out for a music festival. Does waiting for the concrete mean that cabinets cannot be installed over it? It will be a very thin top coat of cement, but possibly thicker in some areas. Also do you think if I just painted it, rather than stain I would need to wait as long?

Without moisture testing (you MUST do this if you have finished concrete/stain/acid etching/epoxy) you won't know what you are up against. Painting garage concrete without knowing if you have a vapour barrier is a game of Russian Roulette. All "fixed" finishes (like paint, epoxy, concrete, acid stain, etc) need a certain level of "dry"...in other words they normally like a vapour barrier. And most garage slabs don't have a vapour barrier...you see where things are going wrong?

If you paint today, it may bubble and peel tomorrow or in 3 weeks from now. The same with "off the shelf" epoxy (which rarely works because you need a very dry slab for it to work). There is a theme going on here!

If you are in a rush, you may have to give up on a "finished concrete" floor because concrete doesn't like curing in winter time (too cold to get it to dry "on time"). Skim coat is meant for sealed concrete slabs...they often don't like to have moisture coming through them (they can flake and crumble).

If this floor is relatively flat/even, I would work with a vinyl product for now. There are loose lay planks or sheet products that will work. You can work with a floating floor of any type (laminate, vinyl, cork, etc) so long as you use a vapour barrier (6mil poly sheeting) underneath. If your garage floor is not flat/even, then you can go ahead and use some leveling compound to help but you may not be able to add coloured concrete because your concrete isn't sealed.

You can...but it won't last very long and you still have to wait for it to cure. And yes, you have to wait for the concrete to fully cure before adding anything to this space (you can paint drywall...but installing cabinets or beds is out). Anything that sits on the floor = waits for concrete to cure.

Contact an epoxy specialist to help with this project. They can have it done in no time (with the fastest cure times)...but you will have to pay the price for their expertise.