I stick by my assertion that grandmothers from hell, such as the one outlined and others mentioned here, should be banned if they are unable to behave appropriately around a new grandchild. Maybe some of that comes from the heart, when my grand daughter was born, the maternal grandmother was in the delivery room, first to hold the baby, my son, the father didn't get a look in, that was only the beginning of other proprietary behaviour too numerous to mention.
I have no empathy with overbearing matriarchs who usually wield some sort of hold over their own children. Fact, to become a grandmother, you have had your shot at being a mother. Take a giant step back, that is the role of the grandparent, to support, not to takeover. A grandmother, in normal circumstances, is not the most important person/s in the baby or child's life, that is the role of the parent/s. It is not a grandparent's place to undermine the parent/s and how they are trying to establish routines. Since we became parents, some things change, research is being done all the time on certain issues, for example when I had my children, we were directed to place the baby on their front when putting them down for a sleep. Findings relating to cot deaths, had reversed that by the time my grandchildren were born and the directive was to place them on their back. Grandparents don't know everything, even if they think they do.
I don't get the whole "I must be alone with the baby" why? it's not a grandmother/s to play mother vicariously with. We did look after our grandchildren when they were babies, only at the parents request. As for massively over stepping the mark with unwelcome advice about weaning the baby off the breast so the grandmother can have her "me" time with the baby and the wrenching baby out of the mother's arms or running off with it, crossing big red lines there. Until she develops a more reasoned approach, I say "yes" ban her and quite frankly get your husband to step up to the plate, particularly as to the personal remarks, and to all the other ways she appears to be undermining you otherwise it'll get worse. You're clearly a very tolerant person OP, but you're dealing with someone who is essentially unhinged. You are the rational one in this relationship, it's time to take control and frankly you're in the driving seat.
Best wishes to you and I hope you enjoy your time with your baby.