From what I remember promo material said she was alive, and yeah a lot of animes show dead characters in OP and ED, but they show the character death in one episode, if the character is killed offscreen without anybody mentioning it again then it's not important enough to show in OP and ED, if Momoka was dead we would already know by now, Mirei or someone else would have talked about her.
Yep, since the moment her design was revealed it was pointed she was alive
That being said is obvious that Mirei thinks she's dead.
Anyways, here's what the first BD will include
Special package drawn by character designer Kaneko
Special Clear Case
Special booklet (setting materials, etc.)
Character CD Vol.1
"Virgin Road" Song: Tokonome Mamori (CV: Izawa Mikako) Lyrics and Arrangement: Shinozaki and Aya
"VALKYRIE DRIVE -BHIKKHUNI-" Bonus DLC Code
"VALKYRIE DRIVE -SIREN-" Bonus serial code
"VALKYRIE DRIVE All-Star Thanksgiving" (to be hold in February 7, 2016) Event ticket priority sale offer voucher
(Cast schedule: Yuka Iguchi, Izawa Mikako, Yurika Kubo, Yoshino Yuna, Asami Seto, Tazawa Masumi, Hitomi Harada, Saori Onishi,Azumi Asakura, Ayaka Ohashi, Azusa Tadokoro)
In Disc
Mini OVA Vol.1
Audio Commentary
Creditless OP and ED
First PV