For the property and implements you listed and stating you are leaning towards the B series, you don't need a sanity check, I think you are correct in assessing your needs.
I would suggest the B series size tractor. I have had both sizes and I think the preference stated in your first post was correct. btw, The
B2620 and
B2920 are still on Kubota's website, but you would have to ask your dealer if there any to be had. There are low hour used Bxx20 series around, but I do think the premium
B2650 your looking at is very nice with some improvements in several details (like the split brakes are now opposite the foot pedal), 3pt hitch, etc.
You stated one acre of lawn, just curious, how will you mow that area? I assume you are not buying a MMM mower just for that. I do agree if your property were different the BX would work fine, but again, for the property, implements and tasks stated I feel a B size will serve you better.
Anyway, good luck with your decision no matter the size or brand...you will enjoy the capabilities!