I'm in.
For those who don't understand Japan Expo stuffs :
The concert will be in a separate hall from Japan Expo. The same hall as MM.'s concert in France back in 2010. Therefore, you have to buy a ticket for the concert (they will be announced and put up on sale soon, according to UP-FRONT LINK ; as Miekie said previously, the 120€ pack is the exact same as MM.'s concert, you have an early access to the concert hall, and you have a bag of goodies, nothing more. Also, know that in 2010, the goods the "premium" got were on sale on Japan Expo stands afterwards, so if you don't have any money, I really think Category 3 ticket is enough.)
But, as UP-FRONT LINK staff said on their Facebook, there are events which are more likely to be announced too. These will surely take place at Japan Expo, so you have to buy a ticket for the convention too, because the concert ticket won't be enough to enter the Japan Expo venue, as it's taking place apart from it.
As for the events, they didn't announce any details, and it'll probably be done soon through Japan Expo's official website.
As far as I know, concerning the handshake, it should be the same as °C-ute last year, because that's the same staff who's running the event. Last year was buy a CD - get a ticket.
Concerning the signing session, it really depends. Japan Expo is really difficult for these, it's either first come, first served or a lottery. Considering the fact a LOT of fans will come for the two groups, I really believe they won't make a draw. It'll be useless, why doing such a thing when you can get a lot of money ? I think they'll make a first come first served system, or the same as the handshake event, buy a goods, one per person, and get a sign.
Also, nothing was announced on Nolife. UP-FRONT LINK just promoted the show on its Twitter.
Edit :
Ah, also, it's Maasa's birthday on 3/7