Hi Nancie,
Yes … latex is a heavy material and also very “floppy” but it’s generally no problem to rotate a mattress or for two people to flip a two sided latex mattress but it’s certainly a little more difficult than a lighter innerspring or traditional mattress which is generally lighter and “stiffer”. Of course if there is a polyfoam core in your mattress it will be lighter than if it was all latex.
This depends on what you mean by a bedframe. If you mean a metal bedframe frame along the lines of the ones mentioned in post #10 here that are designed designed to support a foundation or box spring then as long as it meets the warranty requirements of the mattress manufacturer you will be fine.
If you mean a wooden bedframe (like some of these) then if you are using a foundation or boxspring then there would need to be strong enough support to hold the foundation/boxspring with a center rail and support to the floor (typically 5 cross slats and a center rail) or you are putting a latex mattress directly on wooden slats in the bedframe then it would be best to make sure the slats were no more then 3" apart.
Phoenix