1) I dont think Flameboss does a good job on the lid open detection, but there is a setting to lengthen the time the fan stays off buried in their menu. I'd stick with the fireboard, it seems to do a better job of that, but that is just my opinion. My main issue with flameboss was their probes. I really liked the product other than the probes. But i think fireboard is a better product.
2) Just remember if you are using a controller close that bottom vent, if that is open at all while using a controller you will have trouble maintaining a consistent temp. I did it once just from force of habit, opened the bottom vent for 235 and then setup the controller and walked away, couldnt figure out why my temp wouldnt settle down until i went back and looked and saw what i had done lol
3) Ditch them both until you learn your vent control, do a short low and slow with ribs during the day so you can master the vents, they are really easy on the KK so you'll have a real good idea after one cook without a controller. I just took pics of the vent settings for future reference until i had it figured out.