If you read a bit about it, you'll understand that Apple did not copy the Alto—they did something that was actually way harder. They created a better version of what the Alto was attempting to do, and got it to run on lower-grade hardware they could sell for 1/10th the cost.

But yes, Xerox knew exactly what they were doing when they invited Steve and his team in.

in general you can copy all of someone's designs even without touring. exceptions are when they're covered by copyright or patent

Why would they give away 1m in stock just to look?