Looking at the remaining fixtures. There may be some inconsistency in how we define a "difficult game on paper". You're mainly looking at top 10 sides being the difficult ones, with home vs away being an important factor. I'd consider West Ham away a tough one for example but West Ham at home not so much. Chelsea at home should be considered a tough one for Arsenal despite their league position as it's a big rivalry, London derby and Chelsea's underlying performance stats suggest they're a better side than people think.
City have 2 difficult games left, Brighton away and Spurs away. Brighton seem to be in free fall at this stage though, and Arsenal made easy work of it, so it may just be Spurs away that they'll be worried about.
Arsenal have Villa home, Spurs away, Chelsea home, United away.
Liverpool have Spurs home, West Ham away, Villa away. (we'll ignore Everton away, but maybe that is a potential banana skin because of the derby factor).
Ultimately I think City have the highest likelihood of winning all their games with the remaining fixtures.
Arsenal the most difficult fixtures in my opinion. Although it will help that United will have thrown the towel in on the entire season by the time they come to Old Trafford.