I think the idea that we would stretch either JT or Landry to be very unlikely. Terry, on the other hand, is an excellent candidate (saves $3.9M), and Outlaw isn't a terrible candidate (problem being the savings is only $2M). Note that we could in principle cut Acy's unguaranteed money, but since we'd have to replace him to meet the roster minimum, and he's making the minimum, that would be a lateral move.
But you're doing your calculations in terms of us not crossing the Tax line. I don't think that's the issue here. In fact, I doubt that the current ownership in its push to establish its relevance in the NBA marketplace will balk at paying the tax (even if it does cut us out of one of our last two possible years of revenue sharing).
The number we need to worry about is the apron. The apron is $4M above the tax line, and since we have used the MLE we are hardcapped and not allowed to cross the apron. Since the tax level is $76.829M, the hard cap we have is $80.829M. That's the number we simply can't breach.
Right now, with our current roster we're at about $76.3M. That all depends on the actual price of DC's contract, whether we gave Stauskas the full 120%, and exactly how much of a raise Cousins' contract is going to get (the reported value is the max value from last year, but the actual contract will be the max value from this year which will be about $1M higher). That's for 13 players.
We have about $4M to play with right now. If we stretch both Terry and Outlaw, we gain $5.9M to play with...but we lose about $900K of that because we would have to sign a player at min to get up to the roster minimum of 13. So we can "easily" create about $9M worth of space ($5M before we hit the cap). If we stretch Terry only, that's a hint under $8M to bring in IT (or the fruits of a sign-and-trade). Keep in mind that we'd want to leave a little bit of a buffer. Because if we got any injuries, we couldn't go over the apron, even with minimum players, to replace anyone who got hurt. We could be walking a real tight rope here.