Your fur ones are mink, not weasels ,which do look alot alike but weasels are alot smaller and do not tend to come out during the day. Mink are very abundant around the area now and were probably looking to make the muskrat hole a home not hunting muskrats. Mink prefer fish and duck eggs, even know to raid chicken coops ..... they are meat eaters but very doubtful they would try to take a muskrat. They are probably going thru their spring change of coat and the white patches on chin may not be as visible as in other times