Well, 12"x18"x8" does not leave a lot of room for much - figure the pot will be 6" or so tall, and the lights will cut off 4+" off the ceiling - you got an 8 inch tall plant. Definitely need to LST or something to get the most out of it - and even that won't be much with ~ 60W of CFL. The plus side is that heat won't be much of an issue, and smell won't be much of a factor til flower time, and then only if stealth is an issue, as one small plant like that won't smell like 50 flowering ladies..

If you have some bagseeds, then I'd start with those, see how everything works together, make sure theres not much of a heat issue. Maybe even grow a test pepper plant or something first - if you get "caught" then imagine the look on their face when you open it up to show 'em some habaneros.

And I dunno what tendril means - I re-read what I wrote and stick by it. Sativas in my experience, smell less than indicas. With such a small space as you are using, an indica is the proper choice for you. They flower faster and grow bushier naturally, and although they smell more IMHO, you'll have much better results.