As far as the tee goes, it would depend where it was. For instance, if you had the 3/4" line come off the T&P and then an air gap and into say a larger pipe (for gravity drain), you could tee after that air gap connection. If the 3/4" line came off the T&P and went straight out of the house, you couldn't use the tee (you would also violate #2 and possibly #5 (if you lived somewhere colder)).
As far as going into the pan, you may or may not be able to do that. It sounds like some areas allow it and others do not. The pan is really made to catch any slow leaks from the tank and isn't designed to be able to take full flow from the T&P. The T&P can (but doesn't always) release a ton of water (which turns out to be a mess if the T&P lifts and sticks open...ask me how I know ). The flow can also splash out of the pan even if the pan's drain line was large enough to carry the flow.
They want the air gap in the same room as if you had it in another room or just outside, someone might see the pipe dripping and not know what it is for or think it is just some "leaky pipe" and try to cap it.
Maybe you can tell us more about where the WH is and what is around it. I think that I would try to run a separate line for the pan (to floor drain, outside, etc.).
Just to show some different opinions on the subject:
Palo Alto: http://www.cityofpaloalto.org/civica...p?BlobID=17800
Arlington, TX http://www.arlingtontx.gov/build/pdf...eplacement.pdf
Auburn, AL http://www.auburnalabama.org/PSDir/2...e Editions.pdf
Basically, some places say "Yes.", some places say "No.", and others say "Yes, only if there is no other way to do it.".
If it turns out that your only option is the pan, you'll just have to check with your city/county and see what they will say. Often, they are fairly flexible in remodelling situations when you are trying to bring things up to current standards.