Here is another data point for anyone that may be interested. If you aren't interested in history, then please just ignore it. I pulled out my copy of "The Essence of Shaolin White Crane: Martial Power and Qigong" by Dr. Yang, Jwing-Ming. Dr. Yang says this on page 97:
Yongchun Quan was derived from Southern White Crane during the Qing Qian Long period (1736-1796). There is a saying that Yongchun Quan was started by the lady Yan, Yong-Chun who learned Southern White Crane techniques from the Buddhist nun Wumei in the mountains of Yunnan Province. Wumei's original name was Lu, Si-Niang. Later Yong-Chun brought the techniques back to Canton, where they became the Yongchun Fist.
Now, I'm not saying that this proves anything just because Dr. Yang wrote it in a book. I note this just to illustrate that here is one well known White Crane master that supported a Wing Chun & White Crane connection at least as far back as 1996.