With regard to #1 and #2 I'd make the recommended stops but be prepared to ascend if there was ANY change in breathing and if possible and practical shoot a bag or smb in an attempt to warn those on the surface of the emergency. I would probilily head straight to surface in my buddy's breathing was anything but normal.
On point #3, I'd head straight to the surface and if possible and as soon as possible begin implementing procedures for missed deco stops for myself.
It is when dealing with #4 (and the subsequent clarification by Warhammer) that many other various factors can come into play. #4 to my mind brings the rescuer into conflict with several "rules" with regard to diving and emergency response. First is the classic DIR rule #1 so if I undertook a (planned or unplanned) dive that in which I would incur a significant deco obligation without proper diver and surface support then I'd definately be pinning the needle on the stroke-o-meter and probabily deserve what I get. Remember the recent death of Garrett Wienberg and the IANTD training disaster a few years ago in West Palm Beach, both of which occured under similar circumstances. Additionally, #4 bring one into conflict with two of the "Golden Rules" of emergency response. The first is "Do no harm" and the second is "Don't create another victim(yourself)." By not ascending asap one is more than likely do harm to one's buddy by delaying access to EMS. But, OTOH, one certainly doesn't want to injury one's self. In some circumstances ascending to the surfaces not only harm both diver's but could kill them. As an example, when one dives around here during the off-season or off-peak hour (ie mid-afternoon weekday) or at a remote infrequently used site, it is possible to arrive at a dive site and see, say, 10-15 diver or no other divers at all gearing up for their dives, in the winter it is very often a buddy team finds themselves the only ones at the site, but when one surfaces there is nobody around. They are either still down or have gone home. In this case it is possible that a direct ascent to the surface could be a death sentence for both divers. Also bear in mind that a rescue is generally requires a large amount of energy and activity on the part of the rescuer ergo if the rescuer surfaces with victim the act of proceding with a surface rescue could, theoritically, exacerbate any DCI in the rescuer thereby rendering the rescuer incapacitated or dead.
Regardless, #4 is FUBAR and would probabily result in the death of at least one diver if not both.
Anyway I've ridden the clock enough here at work and it time to go home. Sorry to leave in mid-thought.
Sorry to ramble but you guys should be used to my rambling posts by now.
Peace and hoping none of us have to come face to face with #4,
Sam