Funny. Both kobolds and rats are OGC, no problem. Contrarily to things like mind-flayers, the name wasn't an invention of WotC (or TSR before).
[Trivia Time: Kobolds are earth-spirits, or earth-faeries, that keep and guard the treasures burried below, whether they are artificials (like a treasure chest hidden underground) or natural (like anything that humans have mined). They are especially important to miners -- if the miners are friendly with them, and leave them small offerings, they will lead them to veins of rich ore by knocking on it to guide them by sound; but if the miners don't, they'll provoke cave-ins or firedamp blast. The metal "cobalt" owe its name to the kobolds.]
You may want to do a search on Google with kobold +"small humanoid (reptilian)" (technical terms to be sure to have a correct link, and the name of the creature), Google will propose you an HTML version of the page.
Yep. Otherwise, there's no point of using the SRD only. And you'll probably want to include the d20 STL as well...
Of course, if, as I suspect, that adventure will be put on the Net for free (i.e., it's not something commercial), you don't have to follow the strict rules of the OGL and d20 STL, and may use any IP you want.