Just my $0.02 but if you consider that a heavy duty rotary cutter needs roughly 4 to 5 PTO horsepower for every 12" of deck, and if you are planning on using a 5' rotary cutter, then you'd want a minimum of 20 PTO HP, and it would be pretty reasonable for want 25 PTO HP. For light duty cutters and light duty chores you could certainly get a way with 19 PTO HP, but my general feeling with trucks and tractors is that you want to have more capacity than you know you will need. It sounds like your tasks will include a large percentage of rotary cutting, and if that is the case then you will be pushing the CK25 to its maximum potential, but you will be within the normally accepted range of power for the 2615.
I typically am not one to suggest that bigger is better, in fact I believe that 'right sizing' your tractor is the best long term solution based on your tasks. So if you follow that suggestion, then the CK25 simply falls short of what your planned needs are. I'd suggest you might want to consider the CK30 if you are looking at the Kioti, but that will likely cost $1500 to $2000 more than the Mahindra 2615. Within the Mahindra brand the 2615 looks like a good fit.