, welcome to TrekLit!
I'll answer a couple of the questions:
-I know from years of lurking here (it took me awhile to figure out how to create an account and I missed the AOL Star Trek boards :>) that you don't HAVE to read book X to enjoy book Y. But whomever created the Lost Era books has confused the hell outta me. For starters, do you read only half of KRAD's the Art of the Impossible and THEN jump to Well of Lost Souls... and then back to KRAD's book? The year labeling doesn't make it clear.
For the Lost Era books in general, do they tell an overall story arc over ALL of the books... so it makes it MUCH more enjoyable to read them all... or can you stick with select books if I'm picky about characters?
Don't jump around the Lost Era books, each book is a standalone, you'll definitely get more confused trying to read them in chronological order. In fact, the only common thread between the books is that they all happened between end of Kirk era and beginning of Picard era, (and Elias Vaughn, he's everywhere! j/k). As far as I remember, there are no crossover elements between the books.
-Part 2 of the Lost Era. Is Christopher Bennett's The Buried Age the only other non-year (THANK YOU GOD!) labeled book and hopefully a good read (whether you have read the Lost Era books or not)? The cover art for this book has me interested... I just don't want to jump into something all confused.
if you've watched TNG, then you will be able to read this. it has no connection with the other Lost Era books, at least I didn't catch any references. So jump straight in, you'll have no problem whatsoever.
I'll let others answer the other questions, since I haven't read some of the books either.