Blue Planet has his own continuity, just like Inferno has its own continuity and Cold Element has its own continuity (which Derelict is part of).
For example, STR is considered BP canon. STR is not, however, real canon, it is strong fanon at most, and fan-made campaigns and continuities are free to consider it as part of "their" canon or not.
From the time alone yes, but I very much doubt that Derelict happened in the "BP continuity".
I'd check the campaign list. http://www.hard-light.net/wiki/index.php/Narwhal%27s_Campaign_List
This divides campaigns into the appropriate eras and shows which ones go together.
If you look at the released campaigns thread, http://www.hard-light.net/forums/index.php?topic=70582.0, this will give you links to the campaigns.