The 2501 with the BH77 should handle those stumps easily - get a thumb too, and a ripper shank as it will take less soil and pluck out stumps. I cut the 4-8" tree stumps about 2' high and use it like a lever with the bucket flexing back and forth.
Regarding your question on someone driving and someone on BH, is your 2501HST? If so get a pole (like a trash grabber) and move the HST pedal while on the BH seat.
Carl thanks for advice. I was definitely planning on the ripper shank but had not considered the thumb. I do indeed leave my stumps with 2 to 3 feet left to push it around with the bucket but I guess you can do a better with having a thumb to grab it with??? Yes its a HST. I love that HST so easy to work with.