For the first email:
The title appears to be the phrase "KEYBOARD LAYOUT" scrambled up. (Not sure if there's any additional significance to the way it's been mixed up.)
So trying to decipher the body:
In the first row, convert each letter to the letter which appears directly to its left on a standard QWERTY keyboard layout. e.g. J -> H, R -> E, U -> Y. So the first line of the email says "HEY, WANT TO HANG OUT ON THE BEACH> THAT WOULD FUN"
The second line of the email appears to probably be using the AZERTY layout, although there are some inconsistencies (e.g. sometimes you take the letter to the left, sometimes the one to the right?). I assume this is intended to translate to "OH, AND ALSO BRING THE IMPORTANT STUFF."
The third line of the email presumably uses yet another keyboard layout; if so it's not one I'm familiar with. But just using context and some cryptogram solving skills I've guessed that this translates to "LIKE SUNSCREEN."
As for the rest of the puzzle:
At this point given the number of inconsistencies and errors in the first part of the puzzle (assuming I had the right method of solving) I'm not wild about continuing to try to figure out the rest of it. It would be very frustrating to try to solve only to find out that some parts of it may have been transcribed incorrectly.