About the 1983 Suzukimatic (Suzuki GS 450GA). If you got it for $900 or less, wanted it for around town solo riding, won't be too upset when it goes to pot and is just gone or have the means to keep it repaired and were into the neat-o factor of an old automatic bike, it'd be a cool bike to have for a collector or enthusiast. If I had $900 to spend on that, I'd buy it for those reasons. For $600, I'd probably do it.
Since it doesn't sound like either of you are interested in the neat-o collector enthusiast factor and may want a 2 up bike, pass on this one. Or get it for $900 or less for your wife. That leaves more money for you to get something nice and when the auto gives up the ghost, 2 up with your wife on your bike till you get another and pass your old one to her.
As for cruisers, I have one. An '05 Suzuki Boulevard C50. It's 805cc, shaft drive, 5 speed manual, liquid cooled and about $8,000 for an '09. '05s go for $6,800 and lower. Mileage and condition considered, as with any used vehicle. The C50 and it's older cousin, the Suzuki Intruder 800 Volusia, have a huge following. Spare and after market parts abound. People love to modify them. I've put around 7,000 miles on mine in 11 months and I love it. It's mechanically stock with very few body mods; Suzuki padded sissy bar, Sportech windshield and bullet rear signals. we just started 2 up on it and it does the job. People 2 up on these all the time.
In general, if you want a cruiser for any thing more than around town, back roads and the occasional cross town highway rides or any 2 up at all, get at least a Honda VLX (often called a 600 but I thinks it's really 583cc) or bigger. 250s will do 60+mph, but not for a daily driver and no 2 up unless you're both squirrel size. Daily highway use will kill a 250 cruiser, quick. Slow road use, no problem, a long term bike. 250s are the most common MSF course bike. 500s are better, mostly found on the small end of sport bikes or standards, but for a few dollars more, you can go bigger and better. For 2 up, go bigger, it's better. A 750cc would do. It looks like the 750 is fast becoming the smallest highway cruiser.
Suzuki still makes some 650cc standards and a cruiser. I was on the verge of buying an S40 when I found the C50. My wife is looking hard at an S40 if she decides she wants to drive a bike. She says the C50 is too wide and heavy. It's not, but you know opinions. The S40 and earlier Savage have cult like followings.
One last thing. You may hear it said that noobs should buy 250s or nothing bigger than 650s, tops, and only if they aced the course. Balderdash! I went from The Course on a 250, my first time driving a bike, to an 805. I know two women who went form The Course to a 750 and an 883 Sportster. Be careful. Be adult. Be just fine.
PS. My shaft drive did shift with a feeling the 250 chain drives didn't have. Learning to ride my bike has fixed that. It's one of those subtle nuances.