- Hardware cloth the bottom perimeter like you mentioned and add an anti-dig skirting a minimum of 12-18" horizontal.
- For the roof you'll likely have to add wood or some other more rigid structure than that conduit pipe, to mount it on and be able to support it, even from wind catching it. Without knowing more about your location and weather it's hard to say what that may be.
- For the bedding materials, because it's in direct-contact with the ground, adding any organic material (such as arborist wood chips) will help start a Deep Litter self-composting system that requires significantly less maintenance than other bedding systems.
- Those bottom 2x4s you may consider adding some pressure treated lumber underneath them, which will be in contact with the ground instead; should last a lot longer. I suppose concrete pavers could work, but I'd still go with PT as it may be cheaper. At the same time, I would consider adding a short perimeter wall to contain the bedding from spilling out the mesh walls, cedar fence boards could even work
- Replace the zipties with galvanized wire if you're keeping the chicken wire up top.