It seems to me like 1 Corinthians is good evidence that there was uncertainty in the early Christian Church surrounding the resurrection and whether it really happened in the way that most Christians today believe.
I think we have very little evidence so help us understand what early Christians did believe. And I doubt they were in any way a homogenous group in terms of belief. The notion of the heretics supports this, and that isn't even from the earliest period.
Now one thing which is commonly accepted is that many, or at least some, early Christians saw their belief as the equivalence of a 'doomsday' cult. Effectively that the end of the world was coming really soon and only believers in Jesus got to come out it well as Jesus was coming back within their lifetime. Now if Jesus was coming back very soon (in a few years) then the notion of the resurrection is kind of superfluous - why would he need to die, to then be reborn, to then kind of die again, to then kind of come back again - all within a few years.
So for those people the resurrection could easily have been the return of Jesus from the dead (i.e. the second coming). Now of course when it became clear that there was no sign of a returning Jesus the embarrassment could be readily dealt with by the notion of an earlier resurrection, immediately post death.
So I can see an early christian argument between the 'resurrection as second coming' and 'resurrection as immediate return from dead, followed by second coming'.
Of course we have no evidence for any of these purported events and precious little evidence for the actual beliefs of the various factions of early christians. We only really know what happened once an orthodox view developed within the 'winners' of the debate amongst early christians several hundred years after the death of Jesus.