I think I am finally down to the end of my questions.
Last year in Europe, I added an AT&T international plan for $30, only 200MB data plus $1/minute for calls. Service was iffy at best, data was mostly at 3G. Now it's $40. A quick Google search yesterday brought up Lycamobile. It looks like I could get a SIM card and an international plan that says it includes unlimited minutes to the US and 10GB data (4G or LTE, they say) for €25. The website also says unlimited national messaging, nothing about international. I would have to go to a store in France and buy it to avoid a €25 shipping charge for the SIM card. Sounds a lot cheaper than AT&T. My phones are unlocked so that's not an issue.
Anyway, whether Lycamobile or another company, does anyone have relatively recent experience with SIM cards and temporary calling plans in Europe? Seems like the plans change (usually improving) a lot almost every year.