A wedding present is indeed required. Whether it's monetary gift or something purchased from registry, guests have a year round from the wedding date to see if the couple received it. Others choose to send gifts ahead of time. Either way is fine, if guest won't attend the wedding, it's a customary to send a gift.
Most brides register for gifts, with this the guests will know what the couple needs and things they don't have.
Absolutely, is it appropriate to give money. The guests should seek advise from relatives of the couple if they prefers to receive money.
