Hi Nnmsgst,
You are certainly looking at some good options 
There is more about an all latex mattress vs a latex polyfoam hybrid in post #2 here (and the post it links to) that may be helpful.
There is also more about the most important parts of the “value” of a mattress purchase in post #13 here and the posts it links to as well.
Finally there is more about all the variables that can affect durability and the useful life of a mattress relative to each person in post #2 here and the posts it links to (although you may want to skip this part because two of your three choices would be very durable).
[quote]But would love to be able to buy something less expensive such as this if the experts here thought it would suit our needs:
www.amazon.com/Ultimate-Dreams-Latex-Mat...words=ultimate+dream[/quote]
At your weight I don’t think that 1.5 lb base foam with 3" of latex on top of it would be a suitable choice and both of the other two options you are considering would also be less risky in terms of PPP because they both have options to rearrange or exchange the layers if your initial choice doesn’t turn out as well as you hoped while the Ultimate Dreams doesn’t.
When you have eliminated all the worst options and are down to finalists that are a choice between “good and good” (which you are) then post #2 here has more about making final choices based on your conversations with each of them and all of the objective, subjective, and even intangible parts of your personal value equation that are most important to you. Neither one of your finalists would be a “mistake” and both of them would be a much better quality/value choice than the large majority of the mattresses that are sold in the mainstream industry.
Phoenix