For several years now the Brewers have not sent top pitching prospects to the AFL. Robinson may have an outside chance because he's a reliever, but the Brewers just don't send top SP prospects. They send them to their lab. I will bet money that Gasser and Rodriguez will not be selected.
Mitchell, Devanney, and Black are good calls if Black is back from injury. I'd put Valerio and Brent Diaz as having a good shot, with Darrien Miller and Ernesto W. Martinez as dark horses. My guess is Devanney, one of Diaz/Miller, and one of Black/Valerio/Martinez.
As for pitchers, my guess is the pull from guys like Vennaro, Luis Contreras, Hasler, Zavolas, Meeker, Middendorf.