Upload & Sell: On
This is way OT but Benro & Induro are closer than you think. They're essentially just brand names. Benro tripods were originally manufactured by a company called Yicheng Hardware, that company changed it's name to Yilee Precision Machinery in 2003. The company was renamed yet again in 2007 to Zhongshan Benro Precision Industrial. They changed their name again recently but I can't recall the new name but it has Benro in it for sure.
I think Induro emerged around 2006 and here's the announcement: "Induro is manufactured in a new, state-of-the-art facility by Yilee, Zhuhai, China. Yilee developed and pioneered their own brand under the Benro name, which has become the #1 best selling professional tripod in Asian markets. They have been awarded with the Best Brand, Highest Quality, Best Reputation and Photographer’s Choice Awards 2005 in China."
I think you are correct that the two brands are assembled in different plants, but some components are common. I also think you're correct in that the exterior design of the base, center column lock and leg locks of the Induro models were, to use the MAC Group's own words "... designed and engineered in the US. Worldwide distribution by MAC Group." You only have to look at equivalent models from the two brands to see that they look slightly different. As I pointed out above, if you buy parts they are identical and completely interchangeable.
Benro's relationship with Gitzo is even murkier, and I don't really want to get into it. Suffice to say that Benro quality is high and not necessarily better or worse than Induro, despite what the MAC marketing guys may imply. They both sell a decent product that's very competitive, as do many other Chinese companies. Some of the Chinese companies have pushed older and more established companies to innovate as is the case with Benro and Gitzo. WRT Benro and Induro distribution in the US I can only speak to the Benro side and that's a repetition of what I said above; you have to source from mainland China to get their best models. They're selling the Versatile models here but only the flip-lock versions.