Based on this list, the only guys I'd consider manipulating service time would probably be Wiemer, Gasser, and Ortiz. I don't see keeping Mitchell down two months, unless he really stinks by June, and at that point, the risk of losing the extra year wouldn't matter that much.
Wiemer and Gasser because it's only 2 weeks, and Ortiz because I can picture him becoming Adames-level good, where an extra year is pretty nice to have.
I've avoided making many predictions about the opening day roster/total ABs this season because it seems to me that the scope of possible performance outcomes are so, so broad, and of course... injuries. But I would predict Wiemer will need to put together a month or two of strong AAA production with his new swing before the Brewers would consider him for the 26-man. I also think that Gasser and the rest of the pitching depth will be shuttled in order to manage all of their innings/inconsistent performance.
Ortiz, however, I expect to be a regular rotation guy. A soft-platoon guy. However, I'm also looking at all of the IF depth they've brought to Spring Training, and feel like if Ortiz and Turang look good this Spring, they'll move Adames.