Previous tournaments Lallana has looked OK (probably Euro 16) but I can understand why he isn't In the squad given he has been injured. But I agree I quite like him as a player.
I would definately start Marcus Rashford. He must be given a chance to start vs Tunisia as he is our most direct player and will run at and scare defenses. Plus he is a better finisher than Sterling for England on recent evidence. Therefore I think Sterling should be on the bench. Rashford and Kane on top for me.