I just tried to get Sven and Serana as stewards, both didn't work for me.
I'm guess a bug is preventing Sven from being a steward in your game, since a few posters here have turned him into a steward successfully. Serana though, no one has managed and is probably not "stewardable".
I was also able to get Sven as a steward. I just need to find a female that you can epuip with tavern clothes, damnit --- "All your sweetrolls are belong to me." Video play throughs at - http://www.youtube.com/user/DreadArkive
Wait wait... I thought someone said that marcurio was bugged.. and that even after accepting the steward job that he'd still go back to Riften or something --- VexNoFace likes it rough. Older, Relaxed gamers with mics, PM me if you want teammates for GR:FS or BF3
As far as materials go, I've made a spreadsheet. It can be edited to reflect how many rooms/furnishings a person wants to build, and automatically updates the total number of materials needed. (It's still a work in progress.)
https://docs.google.com/spreadsheet/ccc?key=0AkzmPthdFhCqdFRrQk5udC1oQjUyZmRhdEJkb0oxSkE --- Why don't you have a pork bun in your hand? Now Playing: Heroes of Ruin --- Minecraft --- Skyrim