Hi SheezaRestlessSleeper.
Welcome to our Mattress Forum. 
No paid reviews here - and truly, even when people are genuine in their reviews, you should always throw a bit of caution to the wind where other’s experiences are concerned. While hearing others opinions can be useful, people often review mattresses far too early after receiving them, and reviews lack specific information about all the variables that can contribute to the suitability of a mattress (like details about the person and the mattress) that would make them more meaningful/accurate. We also suggest reading about the dangers of making a purchase based on reviews here.
And, just to cover all my bases, I would recommend (if you haven’t done so already) reading our Mattress Shopping Tutorial and our Mattress Durability Guidelines to help you get an idea of what kind of mattress may be most appropriate for you in terms of support and durability.
As hot sleepers, I’d suggest steering clear of memory foam. There are some great nuggets of information about that by Mattress to Go here and Phoenix here. Memory foam heats as we sleep, and compresses (and our bodies sink further in, trapping more heat). Latex sleeps the coolest of all the foams. You can read a little bit about both options as comfort layers in their respective articles: Memory Foam and Latex.
A hybrid is a smart option for someone who is looking to sleep a bit cooler as the springs allow for more air flow than an all foam configuration (as you pointed out in your post already!).
You have quite the list of mattresses you are considering. Nest, GhostBed, and Flexus are all Trusted Members on our site, meaning we think very highly of them and believe they compete with among the best in the industry in terms of quality, durability, transparency, and more.
I’m not especially familiar with the other 3 mattresses you listed, and without knowing your height/weight and the specifications of those mattresses, it’s hard for me to make any meaningful commentary there. If you happen to come across those specifications, you can cross reference them with our Mattress Durability Guidelines linked above. I’ll also leave this resource with you so you can evaluate whether or not they meet your standards in terms of transparency.
Keep in mind that it is important to have a detailed conversation with whomever you choose to purchase from and provide them with your stats, body type, sleeping styles, general preferences and history, some general information about your current mattress, or what you have tested, and any other specific information or circumstances that could affect your choice of a mattress so they can help you choose which may be your best fit from their inventory.
NikkiTMU