Nokia has shown over time that #1 & #3 aren't realistic. As for Android (#2) vs Windows 7 Phone (W7P), you can make a strong argument for either's adoption.
W7P is currently not a market hit. As you mention, Microsoft has cash in the bank, and they are not going to give up (see xbox, search, etc). Given a couple generations of W7P development, W7P will look like Android today (read: usable).
Nokia may eventually be relegated to a commodity hardware maker, but they do benefit by adopting a modern, competitive mobile OS (as opposed to their current in house options). The worst case for Nokia may look like Motorola. (In that Motorola was bleeding post-RAZR, adopted Android, and are now doing fine even though they don't create the OS.)
W7P is currently not a market hit. As you mention, Microsoft has cash in the bank, and they are not going to give up (see xbox, search, etc). Given a couple generations of W7P development, W7P will look like Android today (read: usable).
Nokia may eventually be relegated to a commodity hardware maker, but they do benefit by adopting a modern, competitive mobile OS (as opposed to their current in house options). The worst case for Nokia may look like Motorola. (In that Motorola was bleeding post-RAZR, adopted Android, and are now doing fine even though they don't create the OS.)