Yeah the level thing is leftover from a previous version. It goes by rank now, sorry about that I'll fix it ASAP.
Hit dice are what determines the HP of the creature, if a creature has a Base Hit Dice of 8 that means it has 8 HP. I use Hit Dice because sometimes I like to use bestiaries from other games and they generally have the HD beside the average HP level.
As far as land goes, I thought I had done that but I think it might have been a previous version before I mathed out the price of goods. I'll have something rudimentary put together when I get back to town.
Generally speaking though I would price the land at 5,000g with nothing on it and if it already has structures you would just add the price of existing buildings. As far as a build limit, I would just always assume you have enough land to build what you want (within reason).
Thank you for showing interest! It's nice to see people playing something I've put so much time into! :D