Running the vent up inside the exterior wall directly behind the shower drain does sound like a logical approach, especially if converting to a wet vent is beyond your current skill level. If you've found a straightforward way to keep it as a dry vent, that's great.
Option 1 involves replacing the current single sink with a new single sink in the centre, which would require moving both the water locations and drain. This would definitely be a more involved job as it entails adjusting the plumbing to accommodate the new layout. You'd need to reroute the...