Who were best take on all comers HW opponents-& who da-best by weight. Also best never Champions?

In this case consider who were the greatest HW contestants in a real world battle.
Say they formed a team & fought against all other possible opponents, each at their very best-which guys would have the best record?
In a neutral rule set between eras, but rules enforced, so say no excessive holding allowed.

If you find size most important, maybe you go with someone recent, say a Klitchko or Lewis vs./with their best opponent.
If not, maybe you pick FOTC Ali & Frazier for absolute best. At least they are among the front runners for lb. for lbs. So we consider they were 215 & 205, = 210 lbs. as their average...
Would 2 sub 200 lb. fighters be good enough to best them lb. for lb.? Would Louis or Rocky make that cut?
Fury fought anyone good enough to make the list? Bowe vs. Holyfied 2? Tyson with anyone he lost to?

Lastly, who would do best in a round-robin tournament with others who never held a belt?
In this argument the more recent guys have a disadvantage, because there are many more titles.
So for example maybe you pick Ike vs. Tua as your Dream Team...

Consider the advantages of having 2 different styles on the same team.
So Ali vs. Foreman you have a great boxer + slugger. Or Ali vs. Liston 1.
They both likely takes out more opposing duos than a set with presumed equal skills, but fighting with a similar style. Say Holmes vs. Norton, even if you found them as good, less stylistic variety does not do quite as well, right?
So considering how good they were during real world matches, we have:

1) Who are the best hypothetical team to beat *everyone*?
2) Who are the best considering their total in ring size?
3) Who are the best pair who never held any title?


For fun, describe if your answer for any of your answers would be different if these guys all fought as literal pairs against 2 others at the same time!
Either all in all the time, or tag team style?