Lol, when I was reading a few quotes from the new map, Howling Abyss, I saw one of the shopkeeper's quote to Ezreal, saying "Is it true what I've heard about you and Miss Crownguard...hmm?". So like yeah, I have a good feeling about this ship. XD
[link] The LoL wiki link just scroll and scroll and you will find what you are looking for. Also I searched it in google, too many links to give. I hope that could be enough thought. I can't put the link on youtube (don't know why) but you can search it on youtube, the video is titled "[4/12 PBE ] Full Howling Abyss Shopkeeper Dialogue" at around 18:34 you will hear it. The map is getting me excited. XD
Garen and Katarina have worked together (he even defended her in Demacia), if you read some of the journal issues. I remember reading one about Blitzcrank's dating service, that suggested Kat and Garen were compatible, along Ashe and Tryndamere, Nidalee (or was it Janna? I don't remember) and Summoner Bob, Rammus and a Cactus (yes, a cactus). So it has a lot of teasing about that couple, but it actually looks kinda one-sided, if you ask me. Either way, Garen seems to have a fascination for her.
And with Ezreal and Lux... I don't know. I think they just look cute together, since they're like the youngsters/prodigies of the League. That was all for me, lol. But honestly, I think they would look better as close friends.