Pardon the basic questions.
Bike #1 Bianchi Infinito 105 with FSA Gossamer compact crank
Bike #2 (old bike, now rain bike) Late 90's Cannondale R500 with full Shimano 600 (standard crank) - 8 speed

I'd like to upgrade the stock FSA crank that came on the Bianchi with a new Shimano Ultegra FC-6750, then if possible put the FSA crank on the Cannondale (because it's newer but mostly because I want a compact crank on the Cannondale for better hill climbing).

Question 1: Getting a BB for the new Ultegra crank - I see that there are Tigra, Ultegra and Dura Ace level BB and at least on Ebay prices and weight are similar. Is there any reason not to go DA since it's pretty cheap or are they all basically similar? Would this work? http://www.ebay.com/itm/Shimano-Dura...item56473a41a8

Question 2: What if anything would make it possible to use the FSA Gossamer crank on the Cannondale? A link to a product on ebay or online store would be exceptionally helpful. In other words the FSA BB on the Bianchi looks to thread on, but I assume the cannondale would need some sort of a press fit adapter to make it work.

Question 3: If I want to go 10 speed on the Cannondale, I ditch the Shimano 600 RD, get a 10 speed RD (already have a cassette) and will need at least a Tiagra level 10 speed brifter right? (ie, my shimano 600 brifter won't work with the 10 speed RD right?)

Thank you very much for any input.