It still seems like just signing Grant is the best option, assuming the contract ceiling is around $12M. And isn't his QO $12.9, so more than the MLE?
I think that's his cap hold, which is different than the qualifying offer. The QO is $8,486,620.
Yes, right, so the floor is $8.5M and the ceiling is likely $12.4M. So we could get him for less than $12M.
I think you're underselling the ceiling, and thus what we could get him for. Any team that wants Grant for the MLE needs to work out a sign-and-trade with the Celtics. Sign-and-trades are not limited to the MLE, and so if said team finds a third-party to take salary, they could offer Grant more than the MLE if it would induce him sign with their team over someone else. For example, Dallas only has $5 million of room under the luxury tax and $12 million under the first apron hard cap that they are subject to, so they are likely to explore trading a contract to another team to create more room. That has widely been reported as Tim Hardaway Jr. to San Antonio. If they traded THJ, they would create a TPE larger than the MLE, and could thus sign Grant to more than that amount. Likewise, the Knicks are reportedly interested in Grant, but they've already used the MLE. They would presumably look to move Fournier somewhere else, and, again, could sign Grant to a deal larger than the MLE if they made such a move. Grant's agents are still probably bringing up dollar amounts greater than the MLE to most of the teams that are interested, since they'd virtually all need to work out a sign-and-trade, and many of them would be trading away salary in such a deal. So I don't think the C's get to negotiate from the position of "the MLE is your ceiling, so take less."