1) Could you provide a little more clarity on the serum? Is this something that could be made with readily-acquired materials with modern day tech? If yes, Wesker could be allowed to synthesize it within ADI's lab facilities. It would be tightly controlled and he would be monitored during these activities. If no, it would fall under the 'I need a substance that doesn't exist to survive.' In which case, it would be taken care of by a patron Entity and he would be able to maintain himself on ambient terror.

2) Correct! Anything superhuman requires feeding a patron Entity.