Strongest Ive trained with (well past their prime of course):
Ted Arcidi (Mr. 705).
Frank Ciavattone (N.E. Strongest Man 1986, 1-hand deadlift w/ 562 lbs, lifted Dinnie Stones, hundred's of world records in USAWA).
Weakest I trained near (not a lifter) - Shawn Michaels when he was in his wrestling prime. Came into town for a WWE match and trained near us on bench, etc.
Well, he trained light but was in great shape and had to Rassle that night, so not really sure how strong he may have been.