Very interesting, and definitely within the realm of reason. Hurwitz had to include the ostriches for more reasons than "they are funny creatures." There are definite similarities between the Bluths and ostriches but I'd never really thought about how Lucille 2 plays into it.
I can't say I entirely agree with the theory that Lucille 2 is Lindsay's biological mother but stranger things have proven true.
Whatever happens, I hope to be surprised in Season 5/the movie!
Suppose the "more Bluth than you know" line means that Lucille 1 KNOWS that Nellie/Lindsey is the love child of George Sr and Lucille 2 (aka Jessica Tamarind) per the birth certificate. Further suppose that presumed alopeciac Sally Sitwell is the love child of Stan Sitwell and Lucille 2 (she just loves that (fake?) long hair and takes an interest in her career by making her campaign manager). That would make the long-brewing Lindsey/Sally relationship a merrily mixed-up half-sibling rivalry.
Fascinating theory! This would help explain Lucille 2's enormous interest in the Bluths, and her considerable helpfulness at times (e.g. loaning Michael $700K) despite her intense rivalry with Lucille 1. I'm hoping this theory turns out to be true. If so, though, I wonder who the father is?
Edit: Sorry, missed the theory that George Sr. might be the father. But if so, that would make Lindsay the half-sibling of Michael, while I was kind of hoping Michael and Lindsay would get together after the reveal that they're not related at the end of Season 3.
Edit # 2: I also saw the theory that maybe Stan Sitwell is the father, which would make Lindsay and Sally half-siblings. I prefer that scenario, which would make their rivalry even funnier.