How many 88s? 117 right?
How many 717s? 88.
How man mkre 90s? 7.
So park 81 88s as the 717s come in. If ASMs don't matter too much. You won't need any more pilots. DCI goes to DCI 450/325 and with a tweak or two you're 1.56 compliant.
If ASMs matter, given the 739s 1:1 replacement of 81 757s, 8 763s and 7 320s, well you a slight ASM problem. Getting back to ASM neutral is greaty aided by 70 new 76 seaters though. Keep 45 88s could help too. Total pilots required? None if you change the work rules.
If ASMs are to stay neutral. If not, DCI 450 is around 1.2M or so block hours, we're at 1.9M or so you get your ratio.
Btw, going off memory from my spreadsheet, got pulled away.