Hi Mgj48,
These are very subjective questions and the only reliable answer to both of them would be “it depends”.
There are no “standard” definitions or consensus of opinions for firmness ratings and different manufacturers can rate their mattresses very differently than others so a mattress that one manufacturer rates as being a specific firmness could be rated very differently by another manufacturer. Different people can also have very different perceptions of firmness and softness compared to others as well and a mattress that feels firm for one person can feel like “medium” for someone else or even “soft” for someone else (or vice versa) depending on their body type, sleeping style, physiology, their frame of reference based on what they are used to, and their individual sensitivity and perceptions. There are also different types of firmness and softness that different people may be sensitive to that can affect how they “rate” a mattress as well (see post #15 here) so different people can also have very different opinions on how two mattresses compare in terms of firmness as well and some people may rate one mattress as being firmer than another and someone else may rate them the other way around. This is all relative and very subjective and is as much an art as a science.
When you can’t test a mattress in person then the most reliable source of guidance is always a more detailed conversation with a knowledgeable and experienced retailer or manufacturer that has your best interests at heart (which would include Brooklyn Bedding) who can help “talk you through” the specifics of their mattresses and the options they have available that may be the best “match” for you based on the information you provide them, any local testing you have done or mattresses you have slept well on and liked that they are familiar with, any special considerations you may have, and the “averages” of other customers that are similar to you. They will know more about helping you to “match” their specific mattress designs or firmness options to different body types, sleeping positions, and preferences or even to other mattresses that they are familiar with than anyone else so that in combination with your own personal testing you can make the “best possible” choice with the highest chance of success.
Most foam mattresses don’t have or really need edge support in most cases if the mattress is a suitable firmness level and a good match for the person sleeping on it in terms of PPP (Posture and alignment, Pressure relief, and Personal preferences) and the support core is firm enough for their body type. There is more about edge support with foam mattresses (including latex) in post #2 here and the posts it links to.
Phoenix