rabbits can eat squash sprouts, squirrels/chipmunks may go after seeds/plants so you may want to put some wire over the plants until they are up and growing.
the problem with the taller grasses is that you may end up with a lot more mosquitoes... but will depend upon your types of grasses as to how tall they get. you can sorta move some of the vines carefully to mow some of it or leave pathways (and of course mow it when the plants are just starting out). if you just water the plants and any spots they root along the vines you can avoid watering the rest of the grass so that may also help limit grass/weed growth (but in MN you probably will get enough rain anyways).
we've gotten rid of most of the lawn/grasses here and i'd be happy to be done with the rest of it ASAP. more veggies and flowers instead anytime.