Hi Zing,
A solid platform foundation will certainly be supportive enough but a slatted foundation is more breathable than a solid surface. While there is no general consensus about this … you can see my thoughts about it in post #10 here (which you may have read already).
A single core of talalay latex is certainly a good quality and durable material so the most important part of your purchase would be to make sure that it’s a good match in terms of PPP.
Latex is not a temperature sensitive material like memory foam so an electric blanket would be fine.
I’m looking forward to your feedback about your experience on both mattresses.
Phoenix