Hi lvjlt, and welcome to the Mattress Underground 
Sorry your Luma order was cancelled; Luma was a Trusted Member of the site forr try many years, and it’s great you have enjoyed the mattress you purchased last year. Unfortunately, @Luma Sleep is now winding down and will soon be suspending operations (Though they will be honoring warranties for the time being).
As you can see by comparing the Mattress Specifications You Need To Know to the Mattress Durability Guidelines, latex is one of the most durable materials you can have in a mattress; you are correct that different types of latex rubber have different ‘feel’; Talalay is considered ‘bouncier’ than Dunlop (think of the difference between angel food cake and pound cake). If possible, you might want to check out all latex mattresses if both types in local retail showrooms to see how they feel for you both, and if a medium firm Dunlop Latex does feel too firm.
As you may know, any mattress you both find ideal will be based on your Stats (Height, BMI, sleeping position(s), and any underlying health conditions) - thanks for providing those! - and PPP (Posture & alignment, Pressure relief, and Personal preferences)…as you both are lower BMI, the comfort level of the mattress will be a more subjective choice, as sleepers without complex support needs tend to have more freedom on types of materials and mattresses more focused on comfort.
Once you determine if you prefer Dunlop latex or Talalay latex, you can better decide your options. The @My_Green_Mattress Kiwi Organic Hybrid is a very solid, well-built mattress, and they also have very generous exchange and return policies, which may remove some of the trepidation you may have with online ordering. Another Trusted Member of the site, GhostBed Canada has retail partners throughout Canada (you are I believe in the Toronto area?) like Sleep Country Canada, Ashley Homestores, and National Mattress Outlet Plus, who all carry a variety of GhostBed mattresses you can try out in person. In addition, quite of few of the Trusted Members of the site ship to or are located in Canada. Also, there’s Restmore and MFC, and if you want new quality bedding and linens for your new mattress, there’s Takasa, so you indeed have a number of options to find your next ideal mattress…I wish success for you in your mattress-buying journey!
~ Basilio