For the size lake, pulling up on your beach (with a wheeled dolly assist), and learning about sailing and doing it, comfort and fun, a recommendation would be something like the 17-ft O'Day Daysailer.
My first boat was a 12-ft lateen-rig boat with a fixed rudder (not swing-up) and a daggerboard. After getting married, we got a 16-ft Falcon daysailer (with a cuddy) and sailed all over the place with it.
Cuddy: The smaller boats typically don't have a cuddy which is very desirable. Its a place where one can stash things (lunch, jackets, camera, etc.) that can stay out of the sun and water that splashes over the bow. In the case of a couple, it's a place where the wife (typically) can hunker down to avoid some of the spray when the husband (typically at the stern with the tiller) is far enough away to not get soaked.
Swingup rudder & centerboard: Better option than a fixed rudder and a daggerboard.
Jib: Most daysailers will have a jib and therefore can possibly be rigged a spinnaker or code zero option for more exciting sailing.
Trailerable: Easy to take down and set the mast. A boat even a few feet larger will have a mast that is progressively more difficult to set although mast raising systems are helpful.
Cost: 16 > 17 ft is comparatively inexpensive. Cost increases somewhat exponentially with length. Check the used ads. In some ways, this size can be more expensive used than some larger boats in the 20 - 24 ft size as the larger ones require a bigger tow vehicle, larger trailer (replacement cost is a lot),
Trailer: Single axel will do it.
Outboard: 3-hp is more than fine.
Learning: An excellent size boat for learning to sail and to do maintenance.
For going forward, I would support your preferences and would avoid a "race boat" type model and stick with a comfortable style as it would be less demanding on the significant other.
Daysailer picture: Falcon 16, McVey design (Nova Scotia *I think*) by Sterling Boat Company in Rhode Island (or Mass.?) c. 1966. O'Day made a similar model of a newer design that is slightly larger.
Flotation in bow and stern. Stowage under seats.
Falcon 16 at Block Island
Sailed the length of Lake Tahoe in one afternoon (launching at noon, anchoring at South Shore that evening).