Hi, I'm new to the forum and I can only really help you with your first question as I'm also sort of new to Calibre myself. But I have a few anthologies and if I add the & between each author's name the sort option separates them correctly.
Example:
The Mammoth Book Of Special Ops Romance has 20 contributing authors. I added them in the '
Author(s):' field like this:
Shannon K. Butcher & Sydney Croft & Laura Griffin & Cheyenne McCray & Marliss Melton & Charlene Teglia & Michele Albert & Gina Robinson & Shilo Walker & Jordan Summers & E.C. Sheedy & Caitlyn Nicholas & Liz Muir & Nicola March & Gennita Low & Debra Webb & Penny McCall & Rinda Elliot & Charllotte Mede & Rachel Caine
And they automatically sort like this:
Butcher, Shannon K. & Croft, Sydney & Griffin, Laura & McCray, Cheyenne & Melton, Marliss & Teglia, Charlene & Albert, Michele & Robinson, Gina & Walker, Shilo & Summers, Jordan & Sheedy, E.C. & Nicholas, Caitlyn & Muir, Liz & March, Nicola & Low, Gennita & Webb, Debra & McCall, Penny & Elliot, Rinda & Mede, Charllotte & Caine, Rachel
I hope this helps you.