your story changed. is this a trial for anything or are you on the XC team to see if he can get you in shape for TF to make that team? because we don't use the word "redshirt" when you're trying out for the team. it assumes you're making it but being unused bench. similarly, do you not know what your situation is, or do you know exactly the score? second post from you appears to answer your OP question.
if this is real, i agree with the poster who said what is the goal here. if you aren't gonna take XC too seriously, if it's just to sneak around the practice limits for TF and have you officially working out, i'd err 800 prep. because the real test is in november. if you want to give XC some seriousness, you prep like a XC athlete. he said "redshirt" but if you show up looking "starter" maybe he changes tack.
i would consider my plans and priorities, and then this is really a coach convo. i don't see much grey in the plan, he spelled it out. what grey i see is if you are secretly a XC stud you have a foothold there and could run with that opportunity. but if you want that, i would openly discuss it with the coach, who might egg it on or douse it with water if his only plan for you is use XC practices to get you ready for TF 800 tryouts -- and nothing else.