Despite all the advantages that you listed for De Zerbi, Brighton’s results are not very impressive, they are an unstable team and for me they and Roma have equal chances of reaching the next round. Roma are still on the rise since De Rossi's arrival, and will be looking to win the first leg in Rome, although Brighton played well away in the group stage.
I don’t know, in this pair the favorite is not so obvious to me, I think something will become clearer after the first match. Brighton are almost unbeaten at the Amex Stadium so if Roma want to have a chance they need to win at home, failing to do so will make life difficult for them in the return leg.
Brighton Albion performance result are not really impressive yet in domestic league match although success lead as top standings team in UEFA Europe League group stage. Of the last six matches in all competitions, Brighton Albion was only able to get two wins, three defeats and one draw. Its very bad result achievement for Brighton Albion and current standings in domestic league has 8 points remaining with Europe League spot standings.
In contrast to AS Roma's performance in the last 6 matches in all competitions, they managed to achieve three wins, two draws and one defeat against top team Inter Milan in Serie A, I think AS Roma has large opportunity for kicking out Brighton Albion on 16 of round Europe League.