Mourinho needs to do what he did well in the beginning, if Roma plays well in defense, then Feenord will have little chance. Mourinho loves the playoff stages and knows how to achieve good results in them, Roma are not the best team for this, but they can beat Feenord.
Mourinho style matches well with knock-out stages but he needs good players and luckiness to win matches. If players are bad, he can not do anything to win Europa League. I think AS Roma have acceptable quality but they are not a best team in quality in Europa League this season. If they don't suddenly have injuries on their important players and they have best fitness for quarter finals, Mourinho and Roma can go far to semi-final then we can see what they can achieve next.
Sevilla's game is also getting better, but I doubt that they will be able to play on equal terms with Manchester United, ten Hag raised the level of the team very well and proved it in matches with strong opponents.
They are improving and climbing to the 14th position in La Liga but they only have 28 points and are only 2 points more than relegation zone with Valencia and Almeria. Sevilla must be careful and keep up their good form if they don't want to be pulled back to relegation zone.
With this risk, Sevilla will likely spend more resources for La Liga and they will play in Europa League with not full concentration and it gives great opportunity to Manchester United.