If you don't want to bring up Emma into a role where he isn't playing every day, then bring up Roden instead. Kriedler can do the things you're getting from Outman, and Roden fits more naturally in a timeshare in the lineup with Martin than with Clemens, who doesn't really give you anything if he can't hit righties (small sample, but a 79 OPS+ and 40% K rate when you're supposed to have the platoon advantage is a mighty low bar for Roden to clear). He's also 26 with what's likely 4th outfielder upside, so it's not some tragedy if he's not playing every day.
So give Roden Outman's roster spot and Clemens' playing time. The supposed boost to 1B defense that Clemens was supposed to provide hasn't really been there, so I think it's a win all around. This also creates space for Larnach to DH more (and play LF less) as well with Bell/Caratini at 1B more often.
You could also just let Martin sink or swim in a full-time role. But they don't seem like they're gonna do that, so letting him split time with Roden where you let Martin face some righties could be a happy medium, and definitely preferable to improperly treating Clemens like a strong-side leadoff platoon