We went a long time before having to change the helper programs for BD Rebuilder. So much time passed that having the older versions of AviSynth and Haali was causing problems for other video encoding programs (like Ripbot264). And people were complaining.
Jdobbs tested his program extensively before moving to the new versions of the auxiliary programs, but even so there have been some bug reports showing conflicts. To sum up, no, you don't often have to update the other programs that BD Rebuilder relies upon.
You can simply copy the new versions of BD Rebuilder over the existing one and not have to go through the process of resetting anything. This is what I do and have not had any problems doing so.
I like the Pioneer 206 for its burns with blu ray media. The newer LG models are pretty good though, and watching Two Degree's results burning dvds with his LG drive, I've been convinced they are good all rounders (good with various media and formats). LG has never been known for providing firmware updates to older model burners. It has been a sore point for users for many years, but lo and behold, they came out with a new firmware for my old GGW-H20L this year! So I have to take back some of the evil thoughts I've directed towards them.
I think either the LG WH12LS30 or the Pioneer 206 would work well for you. I can't make the decision for you though, and there are plenty of threads floating around the forum showing burn results with the two drives if you need more information before deciding.