No, Ram did not require a bridge to cross over (or even Hanuman for that matter) rather the various devatas who had come as vanaras wanted to serve Him. Never mind, these things are beyond your understanding who thinks that God must be bled to pay for *our* sins. Ram did not kill brother of Hanuman (who would be Bhimasena). Ram killed Bali, the brother of Sugriva and there are multiple reasons for that (e.g. usurping the kingdom, expelling Sugriva and usurping his wife).
