Welcome, you have come to the right place
Firstly, without trying to be rude, it wont be until you start paddling that you will know you are a beginner or intermediate, it has more to do with core stability than it does with general fitness. I was very fit when I came to ski's after a triathlon background but still had to do my apprenticeship in a more stable ski....
that being said, you have the right list, the Fenn XT and Epic V10 sport are two of the more well known stable ski's.
Depending on which Stellar they can be stable.
Then there are the Think Evo and Evo2, and depending on where you are you may find other lesser known ski's such as the Dorado.
If you are fit and dont mind a weight penalty the plastic Spirit PRS does most things well and has launched a few ski paddlers into the sport.
If you are looking at being competitive in the longer term dont buy new....pick up a second hand one as you most likely sell it in a season and then you can splash out on a new ski once you "really" know what tickles your fancy.
or if you are going to be more of a weekend warrior/social paddler get the nice shiny boat and enjoy.
Whatever you do, paddle as many boats as you can, they all have sublte and not so subtle differences in comfort, adjustability, stability and the list goes on.
more importantly if you are planning on paddling in anything over 1-2 foot ocean chop, paddle the ski in it, some boats feel stable on a river but as soon as you get into chop you will know if thats the case. If you cant (some dealers will only let you demo on rivers) look for passing boat traffic and try to get the boat wash to hit you from side on to see how you handle it.
If you let us know where you are we may be able to point you to a group of paddlers that could help by giving you a paddle of thier craft after a group session.
as you find out more keep coming back and asking questions, we all went through the same journey you did although in the past few years a lot more boats have come onto the market which can make the choice difficult... and yet there are probably a lot more used ski's out there for sale as we have moved up with experience.
have fun