As for Group #1 and Group #2...I think you're basically describing the same thing with both of these groups. A politician's "belief" isn't necessarily a fixed fact of nature. Both politicians and the general public are remarkably capable of changing their beliefs when it's in their interests to do so (e.g. the complete 180-degree turn the GOP made on health care reform in 2009, which was necessary in order to oppose Obama). If they had a Republican president urging more stimulus (and make no mistake, Mitt Romney most certainly doesn't fall into any of these groups), it's highly likely that at least some of these congresspeople in Groups #1 and #2 would find a way to get behind it.
Basically, if the GOP had any track record in the last 80 years of cutting spending when they were in power (or even seriously trying to do so), I might be inclined to believe that they would do so again. But since they have no such track record, I don't see any reason to believe that it will be any different next time around.