Ed ---> Sawyer, cause they're both stubborn.
Al ---> Jin, cause no one understands them.
Roy ---> Jack, cause they're both leaders.
Riza ---> Kate, cause they both have a thing for guns.
Hughes ---> Charlie, cause they're both hyper.
Hohenheim ---> Locke, cause they both know everything.
Lust ---> Ana Lucia, cause they're both sluts. (my apologies to the Ana Lucia lovers out there)
Gluttony ---> Hurley, cause... well, it's pretty obvious.
Izumi ---> Rousseau, cause they both lost their child.
Winry ---> Shannon, cause they both lost their parents.
Trisha ---> Rose, cause they're both waiting for their husbands.
Feel free to add more!