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...
"No one is actually dead until the ripples they cause in the world die away." - The immortal Terry Pratchett