Hi PristineReflections,
Thanks for taking the time to share your comments and feedback … and congratulations on your new mattresses
You certainly made great quality/value choices and I’m looking forward to your comments and feedback once you’ve received them and have had the chance to sleep on them for a bit.
As you read in the support system guidelines … An all latex mattress 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 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, or breaking over time. The support surface under the mattress 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. I would suggest that in a slatted support system that any gaps between the slats are no more than 3" (with 1 x 3 slats) although less than that would be better yet.
Either way, since there would be little to no flex in either type of support system (either a steel or wooden bedframe with a suitable foundation or a platform bed with a suitable support surface) which one you choose would make no meaningful difference in terms of motion transfer (and this would be especially true with two twin XL mattresses).
If you choose a steel bedframe and a foundation you can add a separate upholstered headboard to many bedframes. Many wooden bedframes that you can use with a foundation also come with an upholstered headboard. If you choose a platform bed (instead of a bedframe and foundation) then there would be some of these that come with an upholstered headboard as well.
A headboard or footboard would be a matter of aesthetics and preferences and this isn’t my area of specialty or an area that I focus on in my research in terms of sources so outside of the few suggestions for platform beds that are in the reference post hopefully some of the other forum members that have purchased a bedframe with an upholstered headboard that they like will see your post and share their comments and feedback about their purchase.
Phoenix