I now have a Mortgage Lifter that is over 6 feet high but few blossoms

Too much nitrogen being the first thing to think of, but you probably
already realize that with your comment about overfertilizing.

Also, do they get full sun?

Will these plants likely bear fruit once it cools down some (some
days are below 90 but not for long usually).

If the heat is the problem, I think so. Tomatoes should keep bearing
all season, although they can taper off later in the season.