The soybeans can be planted well into June. You are not looking for economic yield, you are just making feed for deer. The corn should get in soon, although it somewhat depends on the maturity days of the corn you have. I would try to get the corn in first. The clover can be planted in mid-August if you have moist soil and "typically" moist falls. The soybeans will be fine going in later, they like heat and deer like the leaves too.