Is the Final Version of the rule book better to use or should I use the Second Edition instead?
Use 2.1 edition on GMT's website
Do the official errata on GMT's web site include all errata?
I'm not 100% sure about this one, but I don't recall any more errata. By the way, the 2.1 rulebook includes all the official errata (8.17.09).
Is there one source that combines all of the rule corrections and/or clarifications?
With rulebook 2.1 you'll be fine
can someone please suggest the best site(s) to obtain all of the corrections and/or clarifications?
Like Andreas said: Fields of fire boot camp
You're welcome . If you have any questions feel free to ask, it's a somewhat tough game