Harris will be for 12 million a season
Crowder at 6 million for season
I doubt Davis will be brought over. Does not even have a mid range jump shot
that didnt stop the lust-fest surrounding biyombo on cb, why would it deter folks now? 
The love for Biyombo on this site just befuddles me to no end!!
Because:
a) We need rebounding and rim protection
b) He rebounds
c) He protects the rim
d) He's young with a chance of upside
e) He could potentially be had on an economical deal
Nobody things that this guy is going to be a star, or that we should build our team around him, or that we should offer him the max.
We just think that if we bust out on the big name free agents, and there's a chance to get Biyombo on a short term cap friendly deal (say, $4m - $5m a year for two years) then he's worth taking a chance on given that he can fill some key needs and (as a bonus) has some upside.
Right now our backup center is...nobody. Bass, Sully and Olynyk are all Power Forwards playing out of position at center. We NEED a backup center, and I'd be perfectly happy giving Biyombo a shot given that he is a great complement to any of Sully, Bass and Olynyk (depending on which is our backup PF).
Of course if we can get a star center (like Monroe) then we bring Zeller off the bench as out backup, and there's no need to go after a guy like Biyombo. But based on past history free agency is completely unpredictable, so if none of those guys have an interest in coming here, you still want to add guys who can improve your team and fill needs.
People are saying they'd rather have Harris, but you're talking about a $10m - $15m long term contract there. I'm talking about a short term low cost trial contract. It's apples and oranges.