I suggest pitching the bugs with the yeast into the wort. I think that gets things going faster. It works well either way, but i think it's faster.
Also, I think you have it totally right with your grain bill. Something gentle, with not too much of anything. 10%ish crystal malt. You're good.
Just as long as you pitch some fresh yeast along with the bugs/dregs. I think you want fresh clean yeast to do the bulk of the ferment, like from a starter or something.
Either way it will be fine. I've done it both ways. It doesn't matter very much, especially if you have a simple balanced recipe.