Welcome, 515; you've come to the right place!
FWIW, I'll share my continuing thought process. I bought my R65 about 2 years ago, and this has been a continuing project for me. I'm a bit short in the inseam myself, and my 1981 is marginal. (At 5'6", I'm about where your spouse is—I can put both feet on the ground, but not totally flatfoot without effort.) The only time I feel really insecure is when I have to stop perpendicular to the fall line (slope), and the uphill foot makes contact but the downhill foot hits only air.)
The saddle is a good first step. For additional lowering, here are a few other possibilities, listed in order of preference, IMHO (effectiveness, weighted by cost, PITA factor, and potential handling tradeoff): (1) shorter rear shocks; (2) lower profile tires; and (3) change the height of the front fork/frame junction point. All these have been covered on this site during the past few months.
Time doesn't permit me to give a fully half-baked exposition of these factors. At the moment, I have a sense of potential lowering factor of the shocks and tires. (Was planning to order and install 11.88" shocks, but had to rearrange my priorities after a stupid driver ran me off the road in my cage two weeks ago—couldn't get her license #, and the cost of new tire (hit a curb in avoiding her), realignment & inspection amounted to >$500.
My SWAG is that shorter shocks drop the seat height as much as 1" inch or so (depending on shock length currently on the bike), and going back to narrower OEM, lower-profile (.80, if you can find them) tires can reduce height another 1/2 to 1"). Playing with the fork can help, but I'm not inclined to do so because reducing fork rake might make an already agile bike "jumpy" in quick maneuvers.
Small and light as it is, I wonder if an R65 is the optimal starter for your smaller, younger family members just beginning to ride. If your budget can stand it, a small displacement (250 max) rice mill might be better.