Hi houstonhris,
Thanks for sharing the specs of the mattresses you are looking at but unfortunately I would need more specifics to share any meaningful feedback about them.
I’ve listed the specs with some comments beside them to gice an indication of the missing “quality” information.
sereni Sleep® Bel Air Space Gel Euro Top - Deluxe
• Overall Height: 15" belaireurotop: This is just total height so there is nothing more needed.
• Super Soft Quilted Foam Euro Top: This is missing the density and thickness of the foam.
• GEL Visco Memory Foam Layer: This is missing the density and thickness of the gel memory foam.
• Softech™ Low-Profile I353 Pocketed-Coil Topper System: Nothing more needed
• High Performance Foam Layers: This is missing the density and thickness of the foam layers.
• 540 Pocketed-Coil Spring System: The gauge of the coils would be helpful (there are more coils specs but this would be fine)
• Foam Encasement for Edge Support: The density of the foam encasement is missing.
• Sereni Sleep® FR Fiber: This is the fire barrier but it help to know what type it was for those that are concerned with this.
sereni Sleep® River Oaks gel Euro Top - Deluxe
• Overall Height: 15" riveroakseurotop: This is just total height so nothing more is needed.
• Super Soft Quilted Foam Euro Top: This is missing the density and thickness of the foam.
• Ultra Soft Foam Layers: This is missing the density and thickness of the foam.
• GEL Visco Memory Foam Lumbar: This is missing the density and thickness of the gel memory foam (this is probably a belly band used to create a zoning effect)
• Softech™ Low-Profile I353 Pocketed-Coil Topper System: Nothing more needed
• High Performance Foam Layers: This is missing the density and thickness of the foam layers.
• 540 Pocketed-Coil Spring System:The gauge of the coils would be helpful (there are more coils specs but this would be fine)
• Foam Encasement for Edge Support: The density of the foam encasement is missing.
• Sereni Sleep® FR Fiber: This is the fire barrier but it help to know what type it was for those that are concerned with this.
If you can supply the missing information I’d be happy to make some comments 
I’m not sure which ones you’ve talked with but there are some latex options in the Houston list here but you may need to call them to see what they have available to test on their floor.
Phoenix