Hi RestlessSam,
You can see some comments about the Novaform Serafina mattress in post #2 here.
There is more information and some guidelines about the different type of support systems (bedframes and foundations or platform beds) that are generally suitable for different types of mattresses and some examples of each of them in post #1 here (the first post in the topic we are posting in) that should be helpful.
There is also more information about metal bedframes in post #10 here. I don’t know the weight limit for the Zinus bedframe but I would tend to look for a metal bedframe with center support that goes from head to foot rather than side to side since it will provide better support for a foundation that also has a center support beam.
Any foam mattress with a polyfoam support core will generally do best with a firm, flat, and evenly supportive support surface underneath it that has minimal to no flex under the mattress and for larger sizes with at least one center support beam that has good support to the floor to prevent any sagging in the middle of the mattress. The components (either a bedframe and foundation or a platform bed) need to be strong and durable enough to support the weight of the mattress and the people sleeping on it without some of the parts bending, sagging, shifting, or breaking with extended use. The support surface under the mattress (which may be slats or a steel or wire grid) should have enough surface area to prevent the mattress from sagging through any gaps or spaces in the support surface over time but still allow some airflow under the mattress. If a foundation has a slatted surface then I would suggest that the gaps between any slats are no more than about 5" (with 1 x 3 slats) although less than 4" would be much better yet.
The distance between the slats with the Classic Brands foundation is apparently almost 5" so I would be a somewhat cautious and I would tend to look for something that is stronger with gaps that are closer to 4" or less.
Phoenix