crossover settings?

Large or full range, no crossover. The crossover settings are only valid in combination with a subwoofer.

Not necessarily, if sub is absent some AVRs will redirect the bass to the fronts (must be set to Large obviously). Front speakers even if FS are usually not really 'full range' or 'large' meaning it goes all the way down to 20Hz so a sub is a MUCH better solution.

Q. what do you typically set the center and surrounds to?... fronts are full range... 40 hz? or 60-80hz?
A: There is no typical answer, it all depends on the spec of the speakers. Generally at least 80Hz. Center maybe even higher.

FWIW, Audyssey (no "the" and a y in the middle there) doesn't select crossover settings. The receiver manufacturers, for whatever reason, insist on keeping that to themselves.

If the surrounds are the identical speakers, then you are an unusual case and without a sub, there's no reason to cross them over at all. I'd set them at "large" (something I can't ever remember recommending before) because they'll handle whatever lows are in the program just as well as the identical fronts, and may keep some load off the fronts if the surrounds happen to have a lot of lows. All IMO, YMMV, Please Don't Shoot the Piano Player, etc.

190: (-3dB) 40Hz – 22kHz
180: (-3dB) 45Hz – 22kHz

Without sub, I'll set surrounds to L (what JHAz said), now I know the specs. It's no good setting XO to 40Hz because the 190 can't handle much below that anyway (it's already dropping 3dB at 40Hz down the slope). No real worries about distortion either way.

If the Center is also a 190 then of course leave it L for the same reason.

With a sub, which can go lower than 40Hz (if not get a better one), then the common advice in the Audyssey FAQ thread is to set all speakers to 80Hz. However it's not a hard and fast rule and the XO can be set down to 60Hz in this case depending on your preference after trying both.

Depends on what the fronts etc., are, how the AVR works, etc.

RTFM!

If you are asking if there is a way for Audyssey to make the recevier change physical settings on the sub, uh, no. The receiver can't turn the knob because it lacks opposable thumbs among other necessities. Check out the Audyssey setup guide and FAQ linked in the Audyssey thread. Generally the advice is to set the sub's low pass as high as possible or bypass it if possible before running Audyssey because you generally don't want to double up on the rolloffs that the receiver will implement when it sets the crossover based on data that Audyssey reports.