[first time 5er]

check this link. http://berkeleybiodiesel.org/useful-...nderstand.html

a Berkely study suggest biodiesel actually adds lubricity to ULSD.
Here is a quote
The other main property of biodiesel fuel that we will discuss is its lubricating properties. It has much better lubricating and a higher cetane ratings than today's lower sulfur diesel fuels. Adding Biodiesel also helps in reducing fuel system wear. The fuel injection equipment depends on the fuel for its lubrication. The biodiesel fuel properties increase the life of the fuel injection equipment. Giving better lubricity and a more complete combustion increases the engine energy output, thus partially balancing for the higher energy density of petrodiesel. Older diesel Mercedes are well known for running on biodiesel.

As for the the fuel system you mentioned. The use of a water separator/primary and 3 micron secondary fuel filter is standard on 30,000 psi common rail systems.
Never heard of nor can i find anything on the effects of dissolved air in diesel fuel but it only make sense that the fuel would be less dense