As far as the MCU characters being drawn from The Ultimates, it depends. There are elements of Tony Stark that are Ultimate-inspired such as using humor to hide his own anxieties and traumas and Hawkeye, as I've mentioned before, as well as Black Widow and Hawkeye's long standing relationship as teamed operatives (rather than lovers). But Cap, Hulk, and Thor are all 616-continuity versions with little Ultimate influence (other than Hulk being the product of attempts to recreate the super-soldier formula rather than a gamma bomb).