Inspector here. Will try to provide a bit of perspective. Please try not to hate us, we are just doing our job. Holding the report till the last hour is a realtor or buyer thing, not the inspector. TREC mandates that the report be delivered to the client in 3 days maximum. Most inspectors deliver within 24 hours, I generally do that evening.
First, keep in mind that inspectors have to follow a standard of practice mandated by TREC, in Texas. Unfortunately, a lot of the standards leave a lot of latitude and effectively say "if the is something wrong with system X, report it as deficient.." But wrong is not always specified. Which leaves it to the individual inspector's subjective opinion. Unfortunately, in our litigious society, it is generally thought better to be safe than sorry, as you never know what a client might decide is a big deal to them.
Second, we do not pass or fail things. The TREC mandated report format is limited and inflexible. If any issue is observed with a system, that system has to be marked deficient. Deficient does not mean the system as a whole necessarily failed (though it can.) But that something that needs attention was observed. Your roof situation is a great example. I call out excessive leaf and tree debris build up as well. It is a maintenance item. It is generally easily fixed, and, yes, it can lead to leaks in a worst case. So in your situation I would have the comment (which tends to be black and white - excessive leaves and/or tree debris build up observed. Maintenance/Cleaning needed to remove.) The roof covering category now has to be marked deficient. When going over it with the buyer, I would explain to them that the roof is new, in good condition with no major problems (presumably), but that minor maintenance is needed now, and will be an ongoing maintenance item in the future for them.
As unlikely as a leak might be, as an inspector, we have to deal with the possible worst case situation and the fact that contractors love to throw us under the bus for some reason. That if it isn't noted and a leak develops, the client calls out a roofer and instead of the roofer telling the client that the leaves are a maintenance item and caused the leak, not his work, he will also give them a scapegoat. "I cannot believe that your home inspector did not call that out for you. He really should have. Blah blah blah." Then the inspector gets a nasty call. Better to note the minor concern and hope to educate the client.
Finally, as stated in other replies, as the seller you don't really care about everything in the report, just what the buyer asks for you to address/repair/pay. Most agents will create an addendum of the specific items that the buyer wants to ask to have repaired. They will usually only send over the whole report if things have become chippy as a professional courtesy because of the disclosure thing. But in this market (in DFW at least) there are so many newbies in real estate that you never know.
Ultimately, the buyer gets to decide what they ask for. I have had buyers fixate on items that I thought were pretty minor or unreasonable to ask for. Often their Agent would try to discourage them in my presence. But if they stand firm, the agent will ask. Then you get to decide what you will do and what you won't. I wouldn't sweat it too much. If all they ask about is little easy stuff, do it and move on. Though from your post, it seems like maybe they sent over the whole report and said fix everything. Again, sometimes buyers want that.
PS. The HVAC register thing IS stupid. Totally disagree with him calling that out. Would be interesting to see what his rationale might be. There are several school of thought as to what is right on that. But they are mostly subjective opinions. I would personally say forget it, if that came up on the request.
You should just look at the list unemotionally, many sellers are surprised and offended by what ends up on the report, and either agree to repair, offer a cash amount instead, or edit the list and counter. It is just part of the negotiations. From the buyer's perspective, it never hurts to ask.