Re: Time travel in the Marvel Universe
Marvel's use of time travel is a bit iffy and haphazard. But then, I've never been much for time travel anyway. List of those who can do it:
Mechanical(Time Machine or objects)
Reed Richards, Dr. Doom, I believe Quasar's power bands let him travel through time, Kang, Immortus, Black Panther(limited), Nathaniel Richards, I believe that the Eternals have a time machine and possibly the Inhumans as well
whoever has the Time Gem of the Infinity Gauntlet(I don't remember who had it after Adam Warlock broke up the gems, I think Pip had it at one point)
Powers/Magic
Dr. Strange, Baron Mordo, Ancient One(most of the truly world class sorcerers really), Count Nefaria(I think), Franklin Richards could if he really wanted to and could figure out how to do so with his powers.
There are also a number of "future characters" or characters who have been lost in the time stream. These are characters who have time traveled to the current Earth 666 Marvel Universe. Generally speaking, they are on one way trips, which indicates that 100 years or so in the future, time travel will become, if not common technology, then common enough that everyone knows about it and can find a way to get to a device(albeit possibly by breaking into some place that has such a device).
Phoenix, Bishop. Cable, Fitzroy(are we sensing a pattern here)