Brick Pit Design/Contruction

Greetings, I have been researching quite a bit here and elsewhere as I am about to build a pig pit that I would like to combo as a grill for steaks, burgers, etc. The main reason I am building it is to have somewhere to roast pigs, which I do about 2-3 times per year. Might become more frequent if I had a permanent place to do it! I grill maybe 2 times per months. Getting it to work great for both is a little bit of a challenge, but here is what I have come up with. A brick rectangle in the same dimensions I currently use my portable blocks to roast pigs. The means 63" x 48" x 30" high. The idea is simple, I'll build a ledge to hold the pig "cage" I have made from rebar. The same ledge could be used to hold a steel grate I'll have made, so the grilling part will be at the far end of the rectangle. By placing rebar in the bricks, across the short side, I can set a firebox close to the grill for my direct heat meals. I'll put coals in the four corners on the ground for my pig roasts. I think this should work, I have large pieces of tin for the lid which lay across the top. Not sure how this would work for grilling, but that's what Iuse for the pig roasting. Here is the layout/design I have come up with, please hammer away and give me any feedback.

Thanks - it is pretty simple but I am worried about having a good lid for the grilling aspect. If I use the flat sheet metal, it may be difficult to move around, and the height from meat will be quite low. I can maybe have a dome type lid made, but not sure how heavy that could get is it is about 20" x 30". Trying to figure out how to hinge it but not sure on that one yet.

Also, I'll be adding an access door at the bottom to stoke the fire when pig roasting, and to add air if needed. Hopefully the one door will be enough. I'll also have some weep hole at the bottom to let water out if it gets in, and will also allow air in.

Okay, I have now decided to leave the rebar out. I'd want to get inside to clean occasionally, and to build the fire for pig roasts or other slow cooking meals. I have a stack of cinder blocks from my previous pig roasts laying around that could "live" inside this guy went not pig roasting. I could set a firebox on those when grilling.
I have plenty of access to time for a lid. If I laminate it to plywood, might be okay for slow roasting, but for grilling shouldn't I worry about the plywood charring?

One thing about grilling I was worried about - the ledge for the grill sits about 4" below the top edge. when trying to flip meat this could be an awkward angle. Maybe I should leave the top course of brick off at this edge for this?

Here is what I am looking at now.