Here are some answers:
1. A date hasn't been set yet. I expect it will no sooner then November 23rd, since the "Will you marry me - design a wedding house" contest runs until November 23rd.
2. There is at least 1 new human pet, but probably two. Shizune has been stated as a NPC, while Sippu was stated earlier as a Human pet, together with Shizune. If my information is correct, there will be no rebirth for pets yet. It is rumored to come in version 6.
3. As far as I know, there's no new skill.

Have fun!