I'm assuming that the hose your talking about is your breather for your head, the one that comes off the valve cover and connects to your intake, this also serves as a hot water relay to your throttle body, but other than a little black stuff on the inside of your intake, it really should be causing any residue such as you mentioned.

Realistically, no, it's not emissions, and you really don't want to disable it. There are many arguments about using breathers on the valve cover side of the breather, but to state my opinion, which is actually based on fact rather than popular opinion, the head as well as crank case needs to be well ventilated in order to run to it's fullest potential, this is why you see many road race cars with catch cans that replace the PCV for better crank case ventilation, which by the way is good for about 3whp on the dyno.

And No, Honda filters do not require oil, as they are paper/cotton composite filters, but they eventually do need to be replaced, I think about every 30K miles or sooner, but that should be causing that oily residue you are talking about.

As far as removing you TB, it may not be a bad idea, but as far as yanking off your manifold to clean it, it's really way over kill, and I probably wouldn't waste your time unless you have another reason to do it. Once you remove you throttle body, hit it from both sides with carb cleaner, and clean it thouroughly with a rag, if the oily residue you mentioned remains, the only thing I could think it would be is lube from either your TPS or Butterfly on the other end????

Try removing the TB and using carb cleaner, just make sure you put the sensors and water line back in the right places. If that doesn't work, then you're on your own.

Good Luck,
Aj