Here's who they would probably be.
Feel free to disagree with me in the comments! I'm just brainstorming here.

Harry = Steve
Because he's hot. Obviously.

Louis = Tony
Because he's a hot mess.

Liam = Natasha
The quiet one.

Niall = Bruce
Because both of them just want to run away and make country music.

Zayn = Thor
Because he keeps leaving.
All right that's it 1D!
Time to stop with this hiatus and this splitting up business. You all need to get back together ASAP because there's an alien invasion and we need all of you....
...oh no.
Sorry Hawkeye!
You can be Nick Jonas.
Dem guns tho...
Accurate, or would you change anyone around? @Cat182BB @KoalaMeztli @Merpz @zaperz @AliseFoxtail @AkiraCondry @ashleykpop @Marichel @Luci546 @namelessx @JessReno @melifluosmelodi @Bakuman247 @KwonOfAKind @Aripendragon @YvonJerzak @ReadAnimateSwim @stoptalkingg @sammsosa @MichaelNeyra @CarissaLeal @katthevampire @DustinAtkinson @randysqwishy23 @DanielMonroe79 @TensaZangetsu98 @shogu12s @txSuspect214 @IsaacAmbrose @umaru4ever @14gamergirl28 @JenneJenne @andreav0707 @IleanaCollazo @KayleeScobee @Sydsocquet @zaperz @Maknaeson @KaitlinUlrich @EoinMoore @lynxcubex10 @daxton @Cat182BB @livjos @ninleo @lostpastaproxy @elijah101 @kayelam @peahyr @ChrisContreras @OrionMasters @hhead232 @AleciaReedy @FannyWard @ypl333 @BiancaMason @nobankai @LAVONYORK @shantalcamara @Arellano1052 @jcl4rks0n