I just went two weeks ago having had a first visit to Batuu in Jan 2020. There definitely are some subtle changes to take in (and not so subtle on RotR). Your family will love it.
I would recruit the fam to all be trying with different phones, laptops app, and website to see what gets through.
I don't know about the VPN needs for overseas guests, but it's worth looking into. (I booked on the website from Canada and didn't have problems, so it's not purely an international issue. It was definitely the Canadian version of the WDW website, too.)