As long as the rhizome is white and firm (alive) and NOT black (or dark colored) and squishy, new leaves and traps will grow once the temperatures start to creep up, don’t worry about the sun having to hit the leaves in order for the plant to grow(initially).
Cut off the black leaves. Then, just repot them like any other VFT: make an indentation that is the length from the top of the rhizome (the white part) to the bottom of the longest root(s) in the growing medium, then insert the plant and pat the growing medium down gently to eliminate empty space around the roots and rhizome. EASY! Oh yeah, I would use a 50/50 mix of peat moss and perlite. Using only peat moss does not provide good drainage, and will result in wet waterlogged medium, which isn’t good for the VFT’s.
Don’t worry too much about them. Two of my typicals completely died back to the rhizome over winter. I repotted them this past weekend, and while in the process of doing so, I saw that there was new green growth from the center. Temperatures here in Southern California are starting to become spring-like, so many of my VFT’s are starting to wake up.
Good luck!