I echo Matt's observations 100%.
As to some of the other advice: I am not so sure
Before firing off my $0.02 it is worth stating that there is no such thing as a "best" boat: all boats are compromises and you will need to decide which compromise best satisfies your requirements. Also, none of these Hobie sailing kayaks are speedsters compared with larger, less tippy, more powerful boats - they are only really sailable in light wind conditions (depending on your willingness to take a few calculated risks) - so don't expect to be competing in the next America's cup. But can you learn on them and do they represent the same sailing experience as a larger boat? Yes you can and yes they do! And the good thing about their limited wind range is that every sailing experience happens on a nice day: no storms/long beats to windward etc etc (unless you want to push the boundaries) just pleasant pottering about under sail in benign weather.
There's little doubt in my mind that the best sailer of the bunch by a country mile is the Adventure - by virtue of the daggerboard - this transforms the upwind sailing performance of the boat which without it is not particularly impressive. With the daggerboard and on a flat sea there is very little difference in the upwind pointing ability of the Adventure vs a conventional sailboat. The same cannot be said of the other non-daggerboard Hobies: downwind & across the wind they're OK but not very capable upwind.
The other thing that the Adventure has in its favour is a longer (than the other singles), sleeker hull shape which makes it easier to propel through the water (& remember sailing speed is also limited by waterline length: longer boats can sail faster).
It also has a better sail to weight ratio (i.e. more sail power per pound) than a fully laden tandem. Sure a one-up tandem may do almost as well as the Adventure in terms of a combination of weight and waterline length but without additional ballast in the empty cockpit a tandem has the disadvantage of always feeling a bit unbalanced - therefore I suspect that, either you will sail a tandem 2 up, or you will have additional ballast on board when solo, both of which make the boat heavier. In my experience the the sailing performance of the tandems across all points of sail compared with the Adventure is a bit pedestrian - but then my Mate loves sailing his Oasis both solo and 2 up (he doesn't seem to mind that it is slower).
So the Adventure gets my vote any day.
As to needing to get a bigger boat to learn on - I disagree. I own 2 sail boats (1 modern classic gaff-rigged yawl and one insane trimaran, both trailerboats) and 3 Hobies (A, AI, Outfitter). The other boats hardly ever get used. The conditions I play in are frequently ideal for any kind of sailing (including kayak sailing) so I can pick and choose which boat I go out in, but the one I end up going for 99.99 times out of 100 is the Adventure because it is just so EASY. All the others require a boat ramp and a motor and a trailer and setting up and this and that and the other - major HASSLES that compared with the Adventure are just not worth the effort. With the Adventure I just drag it down to the beach and off I go.... and as I have said the sailing experience is pretty much identical to a full size yacht.
If you want a jib, by all means: put one on your Hobie. Been there, done that: t'ain't hard to do or expensive and it further enhances the challenge of sailing these little boats, not to mention their light wind performance.
As to the need for outriggers: would you be able to properly learn to ride a bike with stabiliser wheels fitted?! Exactly! You are only going to be able to go so far on a trimaran. So if you want to learn to sail a proper yacht and are confident that you can handle a man overboard situation (caused by a capsize on your kayak) then my suggestion is that you forgo the stabiliser wheels and instead learn how a real sailboat leans to wind and wave and how to use that additional parameter in your sailing skills repertoire - so that when you eventually get back onto a larger boat you will be able to feel and know what the boat is up to.
The more you get out on the water and the more intimate your connection with the "parameters" of sailing (i.e. sail trim, boat trim, wind speed/direction, tide speed/direction and sea state) the faster and better you will learn. I suggest that if you have regular/frequent access to similiarly ideal kayak sailing conditions as me you may well find it easier to get out on a Hobie than any other boat, so you may find that you get out more often and with less HASSLE in your life.
When you are on the water in your sailing kayak you are not get more intimately involved in the sailing on any other kind of sailboat because on a kayak you are so close to/at the mercy of every one of the aforementioned sailing parameters - so your learning curve should be fast, long and highly engaging ! (Just take it gently to start off with 'til you get a feel for your and your boats boundaries/limitations !)
Hope this helps ! And ENJOY!!! These are FAAAANTASTIC little sailboats in the right conditions !