Hi Pasquales,
PrfctChaos makes a good point. However, starting to kite on a twin tip would simply makes things easier while you continue to develop your kite control and every other essential beginner skills listed in the green column here:
www.kitebud.com.au/how-good-were-your-lessons/ I have taught over 40 students how to hydrofoil with a kite over the past 6 years and the ones who progressed the slowest were the ones with the poorest kite control i.e. in their first season of kitesurfing. Yes, habits you learn from riding a twin tip have to be un-learned when learning to foil, but the thing is you already know how to foil.
You don't need to spend that much time on a twin tip (depending on your skills and how often you get to go out) before moving on to a surfboard and then a hydrofoil. This is what makes the most sense anyways. You can of course ignore my advice and get straight to hydrofoiling with a kite right away, but be prepared to get into some difficult situations (difficulty relaunching the kite, tangled lines/bridles, lines getting tangled around the foil, losing the foil, etc).
Most people who get into foiling don't realize how quickly a foil can go downwind when you fall off of it. It's also the main reason why people lose their foils. Keep in mind that in kitesurfing you don't tether the board to yourself as it's dangerous.
In summary, my advice is spend a season or so on the twin tip or whatever time you need to get to the point where you can at least go upwind and do transitions in a variety of wind conditions (light, moderate, strong) and you have gained lots of experience with things like deep water relaunching (in a variety of wind conditions and kite positions), board recovery, self-rescue, etc. Then transition to the surfboard and learn to change your feet while kiting, this could take a while. Then move on to kite-foiling.
Christian