Well seeds do cause a really nasty taste which I think might be sufficient to make someone nauseous. Definitely remove them before packing, then save them for a grow operation or eat them (they're quite nutritious and tasty).

I break up my weed a little, but not too much. If you don't break it up at all and just stuff a nug in there, the air goes around the weed and not through it so it's more difficult to light. If you break it up into 2-4 subnuggets it will have passageways to travel through and more surface area will be exposed to the flame, so you'll get better hits. But if you break it up too much, you get little bits of weed coming through the hole (assuming you aren't using a screen because it's a glass pipe). I like to pack it tight but not tight enough to restrict air movement. If you find you have packed it too tight, empty the bowl, unclog the hole with a paper clip if necessary, then re-pack.