In the past, every time I investigate an MVNO (including Cricket), there's always some gotcha like I can't get a new iPhone model (not even if I bring my own), can't tether, there's no unlimited plan, there's a vague warning that some features don't work (like Visual Voicemail or MMS), or it's on some ultra crappy network like Sprint.
I have spent hours and hours researching plans trying to get around these minefields, but always found some problem that kills the deal. Granted, things change. But before I got on this odyssey again can I just ask you, does Cricket have any of these problems?
Cricket is owned by AT&T and uses their network. You can use any unlocked GSM phone that works on AT&T, plus phones that are locked to AT&T (confirmed with my 6S). For a new iPhone, you would just have to wait till the sim free version came out, possibly earlier if you can get one without being on one of the big 4 carriers. Tethering is an additional $10. Unlimited plan for $65. It's on AT&T's network and in my testing Cricket got the same speed as AT&T, up to 8 Mbps. The only one I'm not sure about is the features you mentioned.
If you are curious to try it, you can just buy a SIM card and pay for 1 month of service. I did that with a backup phone and ran speed test side by side with my 6S on AT&T. It's $40 to try it, but it was worth it to me to see if it was a viable alternative as I would save close to that much each month vs our current plan.