B) there is a court case that says permitting subtenants shall not be unreasonably withheld.

From what I see here, they are not being unreasonable in their requests.The late rent situation is an entirely a separate issue.

I had a tenant like that once it is better to offer them there deposit back and move on to the next tenant.It will not end for them to request unreasonable repairs.  

Nothing unreasonable or un-American about that. 

Sometimes the HA is unreasonable, but I think this is a little too far out, even for them.Although, you know: it is racism.

I have never ordered a sign .. so don't know but does not seem to unreasonable unless they promised you 3 day delivery or something.hopefully they did not just pocket your money and go dark.

Tenants are allowed, however, to present a list within x days of moving in (I think it's 10) showing what they have found as it's unreasonable to assume they'll see every little thing wrong within minutes of taking possession. 

60% of gross rent isn't unreasonable, but you do have to be careful with taxes, flood insurance, etc. 

In addition, then you have a time, date, stamp of how many times you’ve had to address and frequency.It’s very easy to get yearly print out and if heating costs have increased it is not unreasonable for you to expect more in renewal increase- if renewing is an option.

If not on website, just give them a call as a "theoretical" tenant and ask what the recourse would be if not under rent control, but rent increased significantly, or what is perceived as unreasonably...