I made a few hypotheticals here:
https://www.spotrac.com/nba/manage/16881582737782/
* sign Wemby (starting 12.2M)
* sign Sidy (starting 2M)
* re-sign Tre (starting 10M)
* re-sign KBD (starting 4M)
* re-sign Champagnie (starting 2M)
* re-sign Barlow (starting 2M)
* renounce Langford
* renounce Mamu
* renounce Dieng
By my estimation that puts us at 14 players + 2 2-way contracts (Barlow and Champagnie) for 120M with the salary floor at 122.4... you don't need to add 30M, we're almost there with all those moves. Just redistribute that figure, say overpay Tre's first year and have the contract frontloaded ant that's it.