I'm gonna put down my findings here, from what I've learned.

Pick on Easy and pick to enter at #1 or #2, I prefer #1 because I start on the left. Though if you just want a safer run you can pick a later number, but you won't be getting WR.

The timer continuously ticks down unless there's six wrestlers in the match, so the quickest way to beat the rumble is to not have six wrestlers inside ever. That's what my 6:28 does, never let the ring fill up.

Picking the wrestler might not matter as much, but I'd take someone I'm comfortable with. I picked The Rock because he's good stat-wise and he's got all the tools I prefer for this run(Good Finisher to Give breathers, pretty nice gut kick, Decent counter stat). I'd normally avoid people with only turnbuckle/corner/running finishers as I'm normally using grapple finishers for breather stalling.

First thing that you want to do, if you're #1 or #2, is run at your opponent and give them a standard irish whip. This will either throw them over the top for their thing or put them against the ropes. Either way, follow it with a quick gut kick and it should eliminate. If not, just toss them out and then gut kick.

Plan from #3 to #29 is to stalk the next entrant, gut kick them to stun, toss them out and then gut kick again. If a reversal occurs it can get pretty hairy. Be ready to hit a quick finisher to get a breather on a reversal. Anytime you get thrown over the top rope I'd mash the L2 strike reversal button as it's usually too hard to directly counter quick strikes for elims that the AI will throw out.

The main thing with this is you can't let there be six people in the ring, EVER. I mean, you can, but my current WR is done without any ring fill. That always hurts the time because then you have to throw out a person to get the timer counting again.

#30 though, that's where the thing comes in. I played it safe by using the gut kick, throw out, gut kick technique, but you can arguably get better times by a standard throw out/gut kick. Only issue with this is that your last fighter may end up being Lesnar, Goldberg, HHH, Austin, because they usually end up being some of the later rumble entries.

I would not try to do the running attacks for eliminations because they really don't shorten times until the last elimination and the AI seems more prime to be ready to reverse a running attack. It might be faster but some characters are hard for pulling such out. Not to mention the running attack can't be an auto knock down one or it'll just floor the opponent.

Wrestler(NON-CAW) entrance is semi-RNG because even though they can enter randomly, they usually stick within certain tendencies. Lesnar, Goldberg, HHH, Austin usually like to hang around the second half of the Rumble, IIRC.