Hi smankins,
Welcome to the Mattress Forum! … and I’m glad you found us.
USA-Beds (Olejo) isn’t a member of this site so there would be no reason for them to offer a discount to the forum members here (although or course it never hurts to ask any retailer for a discount).
I would make sure you have read the tutorial post here which has all the basic information, steps, and guidelines that can help you know how to make the best possible choices … and know how and why to avoid the worst ones (which would include all the mattresses you mentioned outside of the Aloe Alexis). As you probably know Brooklyn Bedding is a member of this site which means I think very highly of them and I believe that they compete well with the best in the country in terms of their quality, value, service, and transparency.
You can also read more of my thoughts about Consumer Reports when it comes to mattresses in post #2 here and in this topic.
There is more about the different types of foundations and platforms that are suitable for different types of mattresses (including several types of the wire grid platform foundations you linked) in the foundation post here and the glideaway platform bedframe is one of the better versions of this type of foundation IMO.
Phoenix