Okay, so not neutered and still young. Great that he has the wood pellets in the litter box. Have you noticed him using the box well? You may want to temporarily remove the blanket since it may be a temptation for pottying. They like to potty where it is soft, so the softest place should be that box with pellets and hay.
I'd suggest taking away the lettuce immediately. That is a LOT of lettuce to start. It could cause tummy issues which can be lethal-- especially in young rabbits. They have very delicate bacterial balance in their gut and suddenly introducing so much of a new food can wreak havoc. Unless a rabbit was being fed greens along with her nursing momma, then she won't have the enzymes needed to properly digest the greens. That is why the greens need to be introduced in very small amounts to allow the gut to develop the needed enzymes.
I'll link a page on my website for how to safely introduce greens. I'd suggest waiting about a week before offering any greens. Then follow the routine suggested at the link.
https://rabbitsindoors.weebly.com/greens--veggies.html
Do you have pelleted food as well? If so, what brand?
Hay is the most important and you've provided plenty of that, so that is great!
As for the space, don't stress. You've got plenty of time to prepare a bunny-proofed area. Small rabbits need just as much space as an average size rabbit because they tend to have higher energy levels. They need room to run and binky! Unfortunately, there is a lot of misinformation out on the web about rabbit care. The following threads on this forum discuss cage-sizing from reputable sources:
https://www.rabbitsonline.net/threads/recommended-housing-sizes.101068/https://www.rabbitsonline.net/threads/2020-indoor-cages-add-your-photo.96731/
There is a thread for 2021 cages, but I've linked the one for 2020 since there are more photos and posts (for now).