Waring had four birdies on each side in his second round and Otto had an eagle, six birdies and a bogey, while Lynn had an eagle and four birdies for a 65. That left the trio at 12-under 130 after 36 holes.
Chris Doak (64) and Bernd Wiesberger (65) are tied for fourth at 11-under and Alvaro Quiros (67) and Justin Walters (63) are in sixth at 10-under.
As crowded as the top of the leaderboard is Friday, it was more muddled after Thursday's first round, when Lynn was one of seven players tied for first and 29 players were within two strokes of the lead.
Otto and Waring were in the same group Friday and established the early clubhouse lead.
Waring played the par 3s at the Oceanico Victoria Golf Course in 3-under Friday. One of those birdies was among the three he had in the final four holes of the second round.
Otto opened and closed his round with back-to-back birdies. He bogeyed the seventh hole but birdied 8 and eagled the par-5, 593-yard 12th hole for a second consecutive day.
Lynn played bogey-free and also had an eagle at the 12th.