I think Marcus would do well. He's an android, he can get a huge number of upgrades and the list of abilities can be extended about as far as one could want, he (likely) can't glitch, and he could be relatively easy to repair, since he is an android. Humans, even bionic humans, aren't so easy to fix when they're damaged. Of course, if you were to send a few thousand volts through Marcus, he'd be short circuited, so you potentially could take him down with a taser, especially one belonging to an ex-criminal like Douglas (extremely high voltage, as in to an illegal extent). It really depends on who is more strategic.
Joining the powers known of the two i think Sebastian wins by cause Sebastian Can use the energy trasference in marcus plasma grenades,blast wave,energy generation and laser sphere generation reflecting these bionics powers to return marcus doing great damage in marcus , marcus uses molecular kinesis in Sebastian Sebastian make do the same pushing the two in the wall , marcus uses laser vision in Sebastian forcing Sebastian uses flame vision in marcus Sebastian wins the battle laser/flame vision marcus uses saw fingers power and Sebastian active laser pitchfork power starts a epic battle in middle of battle the two uses martial arts marcus emerges victorious in this part marcus uses levitation and eletrokinesis forcing Sebastian uses pyrokinesis to prevent this attack then Sebastian uses energy projection making marcus dogde the attack making a speed fight marcus apears wins the fight but marcus uses eletrokinesis kinesis making Sebastian uses eletrokinesis in full power making Sebastian doing your last moviment after Sebastian chip be fried