I'll answer the ones that I can.
1. Do they offer dessert parties during MNSSHP?
I'm not sure, although I wouldn't recommend it on a party night. You'll waste valuable party time here, at least an hour or more.
2. I'm going to take a wild guess and say that maybe the princess will meet at the new fairy tale hall... Is this a safe bet?
No one knows yet. There is no official opening for the new Princess Hall. Last year Rapunzel, Cinderella and Snow White met their their Princes in Town Square. Aurora met with Prince Phillip in Fantasyland, Tiana and Naveen met at their usual spot. Jasmine met in Adventureland (her usual spot) Belle and Ariel didn't meet for the Halloween party, although they are in their new "homes" now and were regularly meeting for the Christmas Party (note Belle's location isn't a traditional meet and greet, it's a short "show" where she retells the Beauty and the Beast Show. No autographs but you can get photos with Belle afterwards)
3. Photopass ops: cinderella's coach, hitch hiking ghost by haunted mansion, smokey pic by PoC... Any other special photopass ops I'm
Missing?
I can't think of any others, someone else might come along and add in a few.
4. Where is this golden horseshoe? DD4 loves Jessie but I have no clue where horseshoe is...
It's in Liberty Square. They hold Woody's Happy Harvest Roundup with Woody, Jessie and Bullseye. It's not an official meet and greet, it's a dance party and the characters rarely pose for photos unless it's very quite. The later you go the party, the quieter it is. You can take candid photos on the dance floor. Also Jessie meets with Woody near Splash Mountain. You can enter MK from 4pm and you should be able to catch them for a regular meet and greet before the party.
5. Are genie and Abu in two separate lines?
Genie and Abu are generally two separate lines. Aladdin meets with Abu, Jasmine needs with Genie. The two pairs swap out meets throughout the night.
6. Is Pinocchio at MNSSHP?
He wasn't in 2012. No one knows whether he will be for 2013. There have been rumors they he will start meeting regularly again but nothing has been confirmed.