They should do fine being raised together, as long as the chicks are the same size or even a little bigger. I would not put larger keets in with smaller chicks tho... keets are way more active and hyper than baby chicks, and the chicks can end up trampled, stressed and not able to get enough feed or water. Watch for aggression or cannibalism (sometimes keets can be attracted to pecking at the ceres/nostrils on other baby poultry), and I'd feed them a starter feed that's high in protein for the keets (no less than 25%... preferably 28%-30% if possible). And make sure they're not ever over crowded, Guineas need lots of space from the very get-go. You may have aggression issues when everybody gets older from the male Guineas (or started by the males, with the rest of the flock following suit) towards the chickens starting up late this Summer or early Fall when Guinea hormones start kicking in (hormones typically rage Spring thru Fall). Plenty of free range time/space as soon as every body is old enough can help with that. I'd have a plan B tho, someplace else to move the chickens to if that starts happening.
Good luck with your hatch. Going by your user name, if you are in KY that's pretty early in the year for eggs/fertile eggs. Congrats!
