for the second quesiton you need to base the worker on either peon or whisp, just change the model of peon or whisp to peasant, then if you want the peasant to be exactly the same, just with another type of building method you need to copy all the values on the peasant and paste on your new worker.
I'm on a page about incorrect corrections, and spent the better part of like two hours trying to get someone to understand that -5^2 = -25, not 25, and then that post had comments get reposted because that group is self sustaining, and that person was in turn trying to explain what I just explained to them. And I'm taking that as a victory