I would definitely recommend integral color (usually a liquid added during mixing) — that will produce more a consistent and durable tint than a liquid stain or "shake" (powder) applied after installation. I often specify a 2x concentration of liquid tint to be sure the color doesn't look washed out after curing. You can certainly wait to have it polished and sealed, but any stains or wear that have accrued in the meantime will be sealed in.

After the home is button up. New concrete needs to cure for a minimum of 30 days, before any work can be done to it. Waiting until the end is best. The concrete will be well cured.

I recently started a new build and here's what was agreed with my GC and concrete sub:

1. Interior Polished Concrete: this will be done just prior to drywall. As noted above, the concrete needs to cure for 30 days prior to polishing. Polishing before framing would be easiest for the Polisher but a) even with covering protection it would be difficult for framers/electrical/plumbing to do their job knowing the floor is already polished, and b) I don't want the house sitting for 30 days to cure before continuing.

2. Garage Colored Concrete: this will be colored instead of stained. I will cover with a densifier to protect against staining and maybe a sealer if I decide I want some shine to it. But the final color will be integral.

The slab will be poured this week:)

I would want the concrete colored before install but after I would want protection laid on top until time to seal and polish. My advice is to talk to the people installing the floorthey can give you the pros and cons of each choice.