Yes, unless the grantor prohibits such transfer in the original transfer document (Trust, Deed, etc.) However, when the original grantee dies the life estate expires.
If you conveyed your property and retained an enhanced life estate you could release your interest in the property by executing another deed to the grantee that releases all your right, title and...
Yes, it is a right in property and can be transferred or sold. It is very difficult to value and most people have no interest in purchasing such a limited interest unless they are the remainderman.