Is it possible to uninstall just RealBand?

It is fine to just delete the RealBand folder.

Or to install BiaB without installing RB?

When you install Band-in-a-Box, you can uncheck 'RealBand' in the component list.

Any issues with updates during the year?

RealBand and Band-in-a-Box each have their own separate patch installers.

For the forum search, make sure you use the forum search (next to FAQ in the forum menu bar, or in right side bar if enabled), and not the "site search" in the top site header. The site search is a 'google search' of the entire website so that doesn't work well for the forums.
PG Music Inc.