Re: Could you start watching deep space nine from series 3?
(In addition the list, maybe the OP could also watch The Forsaken from season 1 because Lwaxana comes back a few times in later seasons and her relationship with Odo builds on The Forsaken.)
Oh yeah, I forgot about Lwaxana. I suppose it should be watched for completeness, but her other two appearances are fairly skippable too.
...so many different suns...