I think the highest scenario Wigan could achieve is beating Swansea and WBA. Arsenal are on a tear and Spurs won't want to miss out on a UCL spot. That would require us beating Sunderland Norwich and then going into the last game with Wigan needing to win dependent on GD. Not the ideal scenario, but one that's more tolerable than needing a win on the last day.
Most likely, I think Wigan will pick up a win and draw between Swansea and WBA and we'll beat both Norwich and Sunderland, having us safe for the last game of the season.
It should be noted that since the end of January (the horror time), we have.
Won: West Ham, Reading, QPR, Stoke
Draw: Everton, Fulham
Lost: City, Liverpool, Arsenal, United
Arguably we could have gotten a point against City, Liverpool, and Arsenal and probably should have won both Fulham and Everton. Nonetheless, we have picked up wins against the sides around us and I'm confident we'll do the same going forward.
Have a little faith people.