IMO, with both having expiring contracts and (most likely) wanting long-term deals next summer (despite the uncertainty of the new CBA), either BBD or Perk will be gone by the trade deadline IF (big IF) it looks like Perk will be ready to play 20 minutes in the playoffs.
I think Perk will again take security over top $$, and BBD will again seek a paycheck in the FA market, his first as an unrestricted.
Sidebar: BBD has seriously bad luck: great playoff performance, but no offers due to his restricted status, so he takes the 2-year deal from the C's, only to have that expire right before a potential lockout and new CBA that will probably negatively affect the guaranteed length/money that a role player like him would be likely to get.
I also think, despite the 2-year deal, that Shaq is a one-year rental, and probably won't get more than the 15 minutes that you have here. He's basically getting Powe-esque minutes, and will likely produce well in that time and role.
The other 80 minutes can be split 30/30 with KG, and JO, 20 for BBD, and 16 for Shaq.
Perk, coming back, will probably get no more than 10 minutes, taking a few minutes from (or filling in for an injured or resting) JO and Shaq.
If it looks good, Doc might run a 5-man rotation, with the super-low minutes, and demand a high-level of energy on the boards in exchange for fewer minutes of work. At least that's what I hope.