Garage is wholly unnecessary. Our garage isn't deep enough to fit a car anymore (previous owners' renovation took away garage space), so my Model 3 sits outside. All good - nothing to it. We installed a Wall Connector outdoors and it works splendidly. The Mobile Connector would be fine too. Especially if she can charge at work, you'd only really be topping off at home, or for weekend travel.
Everyone's use case is a bit different but since you're already in the EV realm with the Prius, I'd be wholly unconcerned with that.
The only advice I'd give you is to be careful. Once you have a Tesla, nothing else is the same. I'd plan for them to multiply in time -- with teenagers coming of driving age, you're going to try to find a way to convince yourself they need Model 3's too.
I already convinced myself (and, amazingly, my wife) that the Model 3 I just bought is really for my 12yo. By the time he gets his license, I expect electric cars to be much more commonplace, and I'll feel good about him being wrapped in the safest vehicle ever built. That said, I don't think giving a 17yo a car with the kind of acceleration the Model 3 has is a great idea either... but hopefully by then, there'll be a "teenager mode" - think chillmode++.
But I surely don't think you'd regret it. I think the vast majority of folks who are disappointed with their Model 3 are folks who want to spend Infiniti money on a car they treat like a Bentley. The "panel gap" thing is way overblown.
You're looking at this as a daily driver/commuter car, and the Model 3 absolutely excels in that department.
The tax credit thing is really only $1875 if you wait to the 2nd half of the year - but it makes a great Spousal Talking Point.
Go for it -- you won't regret it!