Solid Hardwood, Engineered and Laminate Flooring - Laminate in my (difficult and awkward) kitchen!!!

Ok people, here's the situation: I have an old kitchen floor that appears to be asphalt tile, probably original to the addition. The house is 100 years old, but the addition is probably decades newer. Still, the style makes me think 20s-50s -- I know that's a wide range but hey. Asphalt tile before the 80s = asbestos + black gunk with more asbestos. Right in front of the sink 1 1/2 tiles are missing, black gunk and all... I thought that stuff was supposed to be impossibly stuck to the subfloor? Anyway, I want to install laminate, and *properly* so I figure I need to do two things to the existed floor: seal the asbestos in, then level it before placing the laminate.

Here's the questions: Is there a product that can do both, or should I do it in the opposite order? Also, how do you measure a floor to see if it's out of level? I'm interested in a quantitative answer, not just "stick a level on it"... how do you get the number 1/8" over 8' or whatever?

Thanks in advance for any help.

You are correct about sealing (encapsulating) the existing flooring material. First the FLATNESS, more important than LEVEL. get a string and run it across the corners of the room at floor level in the corners. Make the "line" tawt and find elevation errors. Note where they are and up or down. Mark the floor if you wish. Then halfway along each wall repeat the process. This will give you an X and a cross. Having identified the location of a potential problem get yourself a long straight edge, 8' if possible and measure the space at the center for depressions and the ends for high "spots". Now you will know if you have to make the floor flat by using a "leveling" compound. At this point have a discussion about the encapsulation process because a solution will be dependent on the flatening possibilities. Frankly, it sounds like an installation Pro might be a very good option.