How do I get an FAA CPL from an EASA PPL? Im looking into getting a PPL, but feel I need some more information since there are a lot of hours involved so I need to expand my idea of the different possibilities. I am from Sweden but work and plan to do the PPL in Italy, and as I understand it there will be no problem getting a PPL in Italy/Tuscany ( anyone heard of the Lucca Areo Flight School ? ) since I can get a PPL anywhere in Europe. 

The plan is to move to the States in approx 2-2 1/2  years from now. There I will need to apply for an FAA PPL but will it be possible to continue on to the CPL in the US as a foreigner ?

As I understood from reading the threads I would need a PPL anyhow to do the CPL, and as I'm not 100% sure I'll be doing the CPL, is a step-by-step way preferable?
First, this question covers converting an EASA PPL to an FAA one. Based on what you said, I'd strongly suggest getting a full private license rather than a foreign-based one. That will probably require some flight training, which means you'll need TSA approval.

Next, when you have the private certificate then you can continue to CPL. In the US an instrument rating isn't required for a CPL but most people get it because otherwise the CPL is very restricted. You'll need TSA approval again for instrument training but not for commercial training. If you do multi-engine training at any point that's another TSA approval, by the way.

Assuming you have the time and money for all the training, your biggest issue will probably be legally entering and staying in the US. You need an appropriate visa or green card for flight training, plus the TSA approvals that I mentioned.