If virtual particles were prevented from annihilating fractions of a second before the Big Rip itself is actually achieved, wouldn't the universe be flooded with real particles creating an incredible amount of mass?

1) This idea is incorrect

2) The idea is correct and it temporarily delays the Big Rip and continuously delays future Big Rips, thus preventing the Big Rip from ever reaching completion, leading to an infinite number of failed successive attempts to complete the Big Rip.

3) The idea is correct and causes such an incredible amount of matter to be created that the universe assumes an extremely high positive curvature and collapses to a point before the Big Rip diverges all distances to infinity.

4) Virtual Particles aren't real (in any sense) so this scenario is utterly retarded (quoted from below by a PF mentor).

#1 & 4. Virtual means not real anyways.. but never heard of them.

I wouldnt think the Big Rip is an instant moment like the Big Bang, but a gradual process. The U began ripping since the big bang like we start dying since we were born, in a sense.

The Big Rip occurs in finite time, where the distance between all points diverges to infinity (in finite time). The subject of this thread is what happens in the fractions of a second before the Big Rip is achieved? Can the effects of the final moment before the Big Rip STOP the Big Rip itself?

This is wrong. The stretching of vacuum modes by exponential expanding spacetime is precisely how inflation generates curvature perturbations. Perhaps you shouldn't call them virtual particles -- they are vacuum fluctuations -- and they can be physically manifested. The Hawking effect is another example of how "virtual particles" can become physical due to curvature effects.

So the Big Rip (which forms event horizons around every point in space) could cause an extreme occurrence of Hawking radiation before the completion of the Big Rip?

Sure. The cosmological constant is doing that right now, although it's not technically a Hawking temperature because it is a cosmological event horizon, rather than one associated with a black hole. It's more correct to say that there is a de Sitter temperature (although that terminology only strictly applies to de Sitter space -- space filled with a CC). I have not studied what happens to quantum modes at the moment of the Big Rip -- sounds like an interesting question, but likely one that can't be easily answered because the Big Rip is a singularity.

The idea here is that you do indeed begin to get serious particle creation as the Big Rip is approached. The long wavelength modes (low energy quanta) are most readily excited by the expansion and care needs to taken to consider the contributions of these long wavelength quanta to the renormalized stress tensor. These authors claim that when this backreaction is taken into account, it counteracts the phantom energy driving the expansion...