How much weight can a floating floor tolerate?
Let's not reinvent the wheel here. No need to lubricate your floor. The key is that every room should allow movement on both axes. You wouldn't want to pin the flooring under cabinets because they're often installed on opposing walls. 

Regarding your bookcases... If they're not built-in units, don't worry about it. Folks use heavy furniture, aquariums, etc. on floating floors all the time. If the floor can move elsewhere it's probably fine. 

Be sure to acclimate the flooring well. Even one pinned side along with severe moisture or temperature change could cause problems.