1) I can (or can not) rollover my Pillar 2 into a retirement savings in the USA
No you cannot, unfortunately. There is no agreement between Switzerland and the US that allows for this (or Switzerland and any other country that I know of). Of course, it may be possible to put all or part of the money in an IRA or similar and benefit from tax deductions.
2) If I've already deregistered, can I still pull the money out of Pillar 2 and purchase a property (as my primary residence) in the USA? Does this save me from any taxes?
Yes. You can withdraw money from your vested benefits account to buy a primary residence. That applies whether or not you live in Switzerland, and whether or not the property is in Switzerland. However, there is no tax benefit. The same Swiss withholding tax will apply as would if you withdrew simply on account of leaving Switzerland for a non-EFTA/EU country. Vested benefits foundations charge fees for both (early withdrawals on account of leaving Switzerland, and early withdrawals on account of buying a home).
3) If I use a vested benefit account, is this normal, safe - acceptable......
--- my thought would be to move my pillar 2 into a vested benefits account to another canton to save on taxation. Then once there to move it to my personal account in the USA
It isn't just acceptable. It is recommended. The canton of Schwyz has the lowest withholding tax. Obwalden is also a good location.
As far as I know, of all the Shwyz-based foundations, the foundation used by Finpension has the lowest fee for withdrawals due to emmigration, but only if you keep your money there for more than one year. In that case, you pay 500 francs.
Liberty charges 600 francs, but there is no minimum time requirement. Tellco also charges 600 francs. The Schwyzer Kantonalbank charges 800 francs.
If you do not have a large amount of money in vested benefits, then Obwalden and the Obwaldner Kantonalbank is worth looking at. The tax in Obwalden is slightly higher than in Schwyz, but the Obwaldner Kantonalbank only charges 100 francs for withdrawals due to emmigration (no fee if you withdraw to an Obwaldner Kantonalbank account).
In every case, I would recommend that you use Transferwise or a similar service to transfer your francs to your US account, as you could lose a lot of money on bad exchange rates by having the Swiss vested benefits foundation transfer it directly to your US account.