Midweek of 16~23 Apr is very likely for one of the games, as there isn't a CL or EL round scheduled for that slot (assuming it still matters for us and/or Chelsea by then). I think this is most likely the slot for the Chelsea game, as it then removes one party's European involvement as a factor for determining the date for the second game.
After that, the options for the second game (say, Everton) are 23~30 Apr or 30 Apr~7 May, depending on how far we get in Europe. If we're in the final (woohoo!!!) then the game will have to be in the final week of the season, i.e. 7~15 May.