Hi Doublemaster,
1. Both V2 and V3 support this setup. V3 will become the stable version once out of Beta. V3 is stable enough for testing and if you are game enough, you could use in production.
2. Yes V2 can handle this setup. V3 has more features, but stock control is still very similar with the exception of the Warehouse screen which gives you a more interactive look at your stock.
3. SambaPOS fully supports barcode scanners.
All of my setups use a combination of Menu and barcodes. I have 3 sites that are Clubs, one with the Restaurant setup too. And 1 retail shop that we are testing V3 at and soon will be running in production.