No issues so far. I've had them in all bathrooms for several years. For an over-shower light you should go with a water resistant halogen rather than CFL. Otherwise CFL's should work just fine. Be sure to use the bath fan to control moisture though.

"I don't want to have the long warm up times etc associated with cfl's since people are in and out of there in most cases."

Not sure what you are looking for after reading this sentence. CFL's have never been instant full-on lights. Even the non-dimming ones take a bit of time to reach full brightness. If any kind of delay is unacceptable then you should be looking at LED's or halogens throughout.

"Any issues with color temperatures?"
In my experience the warm bulbs give the light most of us want. The blue bias or daylight bulbs deliver light that seems to thin and harsh for household use. I've got a couple of neighbors that have daylight CFL's on a couple of lamps and from the outside at night it looks awful. Like a poorly lit gas station on a dark night.

I want it all :-) Some of the cfl's I have take a minute or so to warm up to full brightness. Not bad for my kitchen where the R30's are on all day (fwiw they seem to take the longest to warm up). In a bathroom where you'll be in and out in under two minutes in some cases, a long warm up isn't ideal. Having said that I don't mind if they start out at 70% then slowly warm up.

Extended periods of poor illumination will wreak havoc on my toilet seat and surrounding floor.

Its a small bathroom and its a three light fixture so I'm thinking it will be OK. Its a discontinued model so if I buy it I better like it because I can't return it. Worse case I'm thinking I can swap out the g24 sockets for something else. I'm saving over 50% (its a $500 fixture) so I'll put up with more than if I paid full price.

I have a mixture of cfl's and led's in the rest of my house (my favorite being the Philips A19 LED) so I'm hoping this will all work out.

Try different brands. CFs vary in the amount of warmup they need. A few claim nearly instant full intensity.

IIRC, CCFls (cold-cathode CF, what an LCD computer screen uses) are instant-on. Even better for your usage pattern, they don't show significant adverse effect from frequent on-off cycling. However, they usually cost more and have somewhat lower efficacy than regular CFs. One example is linked below, but note that I have no personal experience with this item and this is not a recommendation.

If all else fails, you might fit lamps that provide enough light when first turned on.

I would strongly advise NOT modifying the fixture and fitting incandescents. The fixture is designed for the heat output of CFs and it may deteriorate rapidly - possibly dangerously - when subjected to heat from incandescents.