Well, he did control a perfect Jinchūriki with his illusion - we all know that by housing a compliant Bijū one can easily dispel Genjutsu. I can only imagine that Shodai's DNA enhanced Obito's Mangekyō in terms of both strength and longevity.
Yet to be clarified what genjutsu he used. However i have a problem with the term perfect jinchurcki when Yagura is concerned. Manga said he had control of his bijuu, however that isn't a perfect jinchrucki. Yagura could very well be in a similar category as km naruto, who had control of his bijuu but was never a perfect jinchrucki until BM.
Anyway yes, Tobi's genjutsu feats is obviously up there
Yet to be clarified although it has been portrayed as some form of ocular jutsu. Also, the manga said that Yagura was one of the quartet who could be said to have true control over a Bijū [You must be registered for see links].
I agree he had control over his bijuu however im disputing whether he had the same relationship as bee and the hachibi and recently naruto and kurama. He could very well have had control over the bijuu however because he didn't have a relationship with his bijuu he couldn't utilise the bijuu dama/Transform into his full bijuu state, etc. Think he was in the category of km naruto control rather than bee/bm control
His abilities were singled out in the same fashion as Bee's; the two were part of the same phrase. Anyhow, there must have been some sort of relationship between Bijū and host for true control to have been touted. Simply relying on the Sanbi for chakra (like KM Naruto) is hardly the type of 'control' that was mentioned alongside Bee. To control is to influence another being's behaviour, and for true control this relationship must've been somewhat two-way, so I highly doubt that Yagura's position can be likened to that of KM Naruto.