I think Arsenal can win both the Europa and Premier League all the need is more more good games and consistency. They maintained a good performance and stat in the premier league as well as Europa in the early games of the season. The remain the favourite to win the Europa but for the PL the will have to maintain the point difference the have over Manchester City because Pep is cooking up some new tactics to test them once the season resumes.
This can indeed still happen but in the current conditions winning the European league and EPL clearly requires a very big effort for them even though at the moment their consistency is still maintained but we also know that Arsenal sometimes change from time to time and cannot be predicted so this it can still happen but quite difficult in my opinion.
All possibilities are still normal as long as Arsenal can maintain their form until the end of the season, Arteta must not be satisfied with the improvement his team is experiencing, he still has half a season left to reach his target.
Arsenal must always be consistent and continue to try to pursue what has been targeted since the start of the season, Arsenal efforts to bring in several top class players have had a big impact in improving their appearance. Arteta must believe that they can win the Europa League and Premier League as long as they can motivate their players and are supported by the tactics that have been used since the start of the season.