I have a couple of questions for today.

1. http://i.imgur.com/8tVJz.jpg
The last sentence is bugging me a little, especially the word 思える. I'm not really sure which meaning is being expressed here. Is it just the simple "can think"? Or is the word being used in a different way here?

2. 嬉しくて俺は思わず口元を綻ばせてしまった。(this one was taken from a game)
Can someone tell me the meaning of 口元を綻ばせる?

思える does not mean "can think" here. It seldom does to begin with.

「思える」　＝　「気がする」 = "to feel (a certain) way"

"I feel this way because it is none other than you, onee-sama."

It means "to break into a smile".

Ah, so that's how it is. Thanks a bunch for the correction. :)

I get it now. And how about 顔を綻ばせる? Is it the same or different?

Same meaning.

I forgot to mention this last time but 「ほころばせる」 is rarely written with a kanji.

Thanks for the reminder. I'll put this in my notes :)

よし！俺が一番近いんちゃう？

Somebody said this (I was the closest!) because he was close in guessing my age after I sang a song in Koebu. what does the "intyau" part mean?

Well, the い is the end of the word 近い.

As for the rest, did he perhaps say 近いじゃん or something including 違う instead? I'm unfamiliar with んちゃう but I have to wonder if you misheard something like 一番近いじゃん.

It was a text, so I did not mishear it.

This is Kansai speech.

「ちゃう」　＝　「違う」
「ん」　＝　「の」

Kansai---------------Kanto----------------Standard
近いんちゃう　＜　近いんじゃないの　＜　近いのでは ないの

"Great! I was the closest, wasn't I?"

Well, I'm happy to see that my two guesses were Kansai and Kanto variations of the same thing :) Does that make me doubly correct?