1 - This depends on what you want to do… those stats look great but are you going to need hidden stats like mercenary band size, or number of swords or mules? There is a project by @Havenstone called “Choice of Rebels” and the author has done a very good job with both individual stats and stats for the “rebellion”
The best thing is to look at different published works and see how the published works you like did it… look at Sabres of Infinity or look at @Lucid 's Heir series…
2 - That is up to you and your story. My story has two main “trunks” where you can be a barbarian prince/princess or you can be an Imperial prince/princess of the Byzantium empire… and each of those main trunks have scenes with choices in them… usually try to limit the choices to three but sometimes it gets complicated … as you can see the more choice you give the more complicated it can get.
My main advise here is write your story true to your vision and the branches and choices should suggest themselves.
3 - There are several threads on posting your demo on Dropbox … let me see if I can search a couple.
Edit 1: Link to updating a dropbox link for your demo here (thanks to @Fiogan for pointing me to this.
Edit 2: Link on getting started with dropbox and steps towards getting published here (thanks to @Arcania the Grand Brownie for pointing this out)