Is there a policy that states the maximum number of working days for Leave/Paperwork to be completed at the company level?

If your commander has a policy, that's the policy. If not, then no. It just depends on the people you have in your training room and S1 ultimately. Some are good and get things done, some don't.

The last two units I've been in the company has said submit leave NLT 2 weeks prior to start of leave date. Other units, I'm not sure if there was one. I can't remember. The two joint units I was in I don't think even the Army Element had a policy. Although my first joint unit had no Army Element for a year. So we just sent leave forms to J1 and they had no Army people up there so they never got processed and we didn't get charged for a year lol.

It's just up to each unit on processing leave or awards. Awards processing might be in the AR but I can't remember.

There isn't that I know of. A lot of times paperwork will get denied and then sit there until it flows back down or gets lost. A commander can make a policy letter stating that you must submit leave 2 weeks before. A commander can establish their own policy. Your commander can also deny leave at anytime.

I would think that would only be a local policy. Could be done at any level but no regulation I know of requires it to be submitted at a specified time in advance of the time requested.