You asked two questions. First - the Hot Spot. With an iPhone 8, this is turned on in your Settings > Cellular. Tap Personal Hot Spot and tap the slider bar to turn it on (or off). https://support.apple.com/en-us/HT204023 For most Androids, its Settings > Connections > Mobile Hotspot. The first time you use it, you'll need to set up a password on your phone; after that, all your mobile devices can access it. The only thing you need to do is turn on your tablet or whatever device you're using and do a wifi search which will show your phone as an available network. Log in just like any other network and enter the password you set up in your Hot Spot setup. It'll log in just like normal and you're all connected to the internet. Turn off your hot spot on your phone when done to save your battery.

I stream Netflix and other apps on my tablet and download books to my Kindle all the time through the hot spot when traveling in airports or other non-secure wifi environments. No one should ever use public wifi if they've got a cell phone with them, and who doesn't?

Your focus should be on learning about wifi calling and how to do it on your phone. In a short time, we've moved from getting local phones to using local sim cards on your own unlocked phones to AT&T /Verizon international calling plans on your home phone and now to wifi calling, meaning that international calling plans are "yesterday", already. For now, though, I suggest you just turn on airplane mode and turn on wifi calling using your home network and see if you have any problems. It works the same anywhere you can log into a wifi network.

If you really, really want to use AT&T's or Verizons international Calling Plans, just log onto your cell provider website and activate whatever plan fits your thinking. You'll probably never use it but peace of mind - it'll always be there. Then, when in another country and you really need to make a call and don't have wifi, all you do is turn off Airplane Mode and your phone will access local towers and work just like you had a local phone without you doing anything. Cost is $10 / day or $40 / week (AT&T) depending on what plan you activated with your provider. Don't forget to turn on airplane mode before you go to bed (LOL, before midnight!) and make sure your wifi calling icon is still turned on and lighted. Easy as can be. Assuming you don't call while driving, its really rare to use the calling plan, and like I said, we don't. Its just backup. (The only "burp" I've had was one day before I started using wifi calling and I was using the AT&T calling plan. We traveled between Orient and Phillipsburg and I lost cell service on the Dutch side. What's the answer to anything? Reboot, right? So I turned the phone off and back on and it worked fine again. I read later that was because we "changed countries" and we needed to reset where we were. LOL! Only in SXM!)

We don't take a phone to the beach, but anywhere else we go usually has wifi, and we get incoming calls through wifi routinely with no cost to the caller or us, so there are no "stored" calls or messages to "come through". We have had voicemails a few times just like normal (we should have ignored them since we were on vacation!). I'm not sure what others in this thread have experienced, but as long as we're on wifi, the phone works just like we're at home and since we really only use the phone around the villa, we don't even think about it. The only downside to all this is being able to log onto the wifi at where-ever you are if you feel a need to be connected 100% of the time. Once at the villa is good enough for us, but I might log in somewhere if we'll be there for several hours. Again, like anywhere, its only a first time login. (Actually, it's kind of a kick to video call someone at home and show them the ocean view while having drinks before dinner!! Hmmm, sad that's not likely at Grand Case right now.)

BTW, both of our phones are set up this way and we use them both when traveling, and we wouldn't duplicate this if costs were involved.

We don't use Facetime or Google chat or anything else anymore - wifi calling on AT&T does it all just like you're at home when you make a voice or video call. Again, as easy as can be. Like moving from a flip phone to a smart phone - once you get current with technology, you wonder why you waited. It's exactly the reason "Queen of SXM" / Sharon closed her cell phone business - it was obsolete.

(after reading my post, I just need to confirm - no, I don't work for AT&T!) LOL!

I hope this helps.