Some comments from an 35xi owner who has changed his oil once!
Note the position of the larger oil filter gasket before removing it. It is in a groove on the filter housing in a position lower (higher?) than you might expect.
Assuming that the 2.8L engine is the same as my 3.0L (N55) (all other details of your oil change procedure seem to match perfectly), the oil drain plug torque setting is also 25 nM.
The oil filter drain plug has a copper washer which should be replaced; it should come with the oil filter.
Torquing the oil filter to 25 nM should result in precise alignment of the two green marks. Or, just use the green marks.
There are a number of sources for the oil filter wrench - pretty much a standard tool which works on lots of BMW engines.
Soaking up the residual oil in the oil filter base is most easily done with one of those high-tech tools, i.e., a paper towel.
Concur that the tilt associated with lifting just the front of the vehicle does not hinder the draining; it may indeed help.
I used 7 quarts of oil and the resulting oil level readout on the iDrive display (Vehicle Info | Vehicle Status | Engine Oil Level) was right at the top of the full mark.
We had the dealer do the first oil change at 15K. The car was telling us something like 18K miles, but the dealer said no, bring it in now. I changed the oil at 22K miles and plan to have the dealer change it at the normal 30K miles point. Am awaiting a report back from Blackstone Labs on that 22K oil. Unless it is much cleaner than I expect, I will continue to do an "in-between" oil change myself, suplementing the dealer's changes.
Some comments on warranty concerns, etc. I think that, as long as you stick to the BMW approved oil and standard (Mann) oil filters (and remember to install the oil filter, drain plug, and oil before you start the engine!), you should have no problems. This oil change is about is as easy as they get nowadays.
For the uninitiated: Unless you're really, really tiny, you do need to lift the vehicle to obtain acess the the oil drain plug. Safety is always an issue when working under a vehicle. You MUST use real jack stands with the correct jack pads or good ramps and make absolutely certain that the vehicle cannot fall. I'd recommend Race Ramps; the're proven and very light and easy to deal with. Don't do it if you don't have the right equipment; your dealer will be happy to change the oil any time you want (and take your money). It is not worth getting hurt for a relatively small amount of money. Indeed, one could argue that, if you need to spend a few hundred dollars to obtain the correct tools, the dealer's cost is well worth it.