Megan
The four seater is to do with EASA law and registered facilities teaching ab initio !
As to learning to fly on a 500, some thoughts
1. Expensive, about twice that of learning on a 300 for instance
2. You will be a better pilot learning in a piston.
3. Probably quicker to do it in a 300 then convert
4. It is reasonably long legged, holds 310 litres of jet ( with normal tank plus fargo ) so that is about 2 hours 45 mins at 130 kt cruise, so will go further than your 206 !
Can basically teach anyone to fly one given enough time and money, after all most of those ex mil pilots on here will have learnt on a gazelle which is basically a French version of a 500 in what it was designed to do.
I would be happy to teach you in one ( I have a few of them )