If the Main Floor is slab on grade, the live load is not likely a factor in design. If it is a structural floor, live load could range from 100 psf to 150 psf depending on occupancy. For special uses, it could be more.
If the Second Floor is used for offices, the minimum live load specified by code is 50 psf, but I prefer to use 100 psf to allow for unknowns such as heavy filing cabinets etc. If the Second Floor is used for storage of machine parts, the live load could be much heavier.
Roof snow load varies with location.
BA