For everyone who said Vince McMahon going to TNA, really? Really? Vince going to TNA is the same as saying Paul Heyman will go to TNA. It's just not going to happen. If WWE were to go bankrupt, Vince would simply retire with the wealth that he has left. Guys like Triple H, and Undertaker would not return to the wrestling biz. Same with Jericho, Big Show, Kane, Rey Mysterio, and Edge. They might make an appearance for a short stint, but they will never stay long term.
Now guys like Randy Orton, Matt Hardy, Evan Bourne, Christian, Kofi Kingston, Drew, Sheamus, Nexus, CM Punk, the Miz, John Morrison, the Hart Dynasty, Usos, R-Truth, Ted Dibiase, Cody Rhodes, Khali, Dolph Ziggler, CM Punk, Jack Swagger, and MVP, they will be looking for work. I'm sure a few will go to TNA, but more will end up going to indy shows or ROH, or another small organization like that.
Now, for your question. Which 5 should TNA go for after the downfall of the company? Here is the list in order of who they should call:
1. John Cena. The Face of the WWE. If WWE were to go bankrupt, John Cena is the first person they should call. If he were to ever set foot at TNA, this would really be a big middle finger to Vince from Dixie, stating they took their top guy in the company. But will they use him right? Probably not.
2. Randy Orton. He is the hottest thing in WWE right now, and is the shadow of Stone Cold Steve Austin. TNA would be crazy if they didn't think Randy Orton would be a benefit to their company. But would he go to TNA? Maybe. Randy Orton has a lot of years left in him. 10-15 years left. That's a lot of matches and potential. Randy would be looking for work, and TNA would be the biggest lure to Orton if WWE is gone.
3. The Miz. Why? Because he's the Miz, and he's awesome. He is pinned to be the next possible Face of WWE after John Cena steps down. He is great on the mic and his in ring skill is improving. Everyone either loves the Miz, or hates him. Vince see's the Miz like John Cena. Hard working, loves his job, and he is dedicated. He is the Mr. Money in the Bank. TNA would have to be crazy to let the Miz go to another promotion.
4. CM Punk. CM Punk is one of the top heels on Smackdown. He is extremely talented and is a multiple time World Heavyweight Champion. Punk knows how TNA thinks, and has friends there. If WWE were to go under, Punk would most likely go to TNA and rule the X-Division and even the Main Event scene.
5. Too many to list. Why do I say this? Because TNA wouldn't be after 5 current WWE Stars. They would be going after a good number of them. Sheamus would probably be the 5th caller that TNA calls, seeing how he is the current WWE Champion at the time of post.
WWE going bankrupt is not a reality. Of course, anything can happen that would cause WWE to go bankrupt, but right now, WWE is staying afloat. If there was any sign of WWE in danger of going bankrupt, we'd see many things change left and right. People would be laid off at an outstanding rate, Creative would be in a panic to get new material to get people drawn to the show, and merchandise prices would go down to help get people to buy them.
I do see a WWE Going Bankrupt storyline in the future, however. When? When Vince McMahon decides to step down as CEO of WWE and give the company to Triple H and Stephanie McMahon, or his son Shane. Only time will tell if that will happen.