Reddit mentions of Live in Tokyo

It was originally added to Amazon Japan as a preorder a month or so (but placeholder info, no art until the past few days when news sites picked up on it) :)
http://www.amazon.co.jp/ライヴ・イン・トーキョー-DVD付-フォール・アウト・ボーイ/dp/B00DDWU6G0/ref=sr_1_4?ie=UTF8&qid=1371564406&sr=8-4&keywords=fall+out+boy+dvd

It was also a pre-release show, so they only played My Songs and The Phoenix (with the latter being the 1st performance of the song, so really not the best one so far). I'd expect a proper large scale live performance to be post-album when they were playing a lot more off the new record.

Bands always do weird Japan-only releases or products aimed moreso at them. Most albums have an exclusive bonus track there, for example SRAR had the 2Chainz remix of My Songs as a bonus. The japanese release of SRAR also had a bonus DVD featuring the My Songs DVD and some sort of album commentary apparently.