i am planing to buy the fire emblem bundle and i was wondering if i could transfer the fire emblem installed game to one of my friends without anything happening to there saved 3ds data and after that would i be able to transfer all my Ambassador games from my old 3ds to the 3ds that i transfered the fire emblem to

From what I know, you can transfer Fire Emblem without a problem (As long as that is the only content preinstalled or purchased from the eShop)
Once that is done, you must wait 1 week to complete another transfer. Once that week has passed, you are able to transfer all your data from your original 3DS data, photos etc, to your original 3DS.
Keep in mind you have a limit to how many times you are able to transfer until Nintendo stops you from doing so anymore. I believe the limit is 7.

Here's a guide from Nintendo Life. But it doesn't matter whether its an XL or not all 3DSes should have the same process for system transfers.

http://www.nintendolife.com/news/2012/07/guide_3ds_xl_system_...

^CAT BUG !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Also, think wisely on whether you really want this system, or not. Clearly you aren't getting this for the game, and solely by design. Think of your priorities wisely. If you Really feel like this will be a great investment, do so, but with that same money, you can buy a 3DS XL, Luigi's Mansion Dark Moon, and another free game.
Or you can get (At least) 5 3DS games.
Basically think through whether you can spend this $200 to your ultimate advantage or not.

I'm pretty sure the receiving system's memory gets completely replaced with the sender's, so your friend would completely lose whatever is on his 3DS in order to receive Fire Emblem.

IIRC it will. You cant send just one thing you have to send everything if that is just the one game that all of your friends stuff will be wiped.

Actually, no. It doesn't you don't need to worry.