1st. You can keep your jump height as it is rite now.
2nd. You don't need other codes with this, only if you want your hack to be named 'codjumper'...
3rd. You don't need to bypass, you can use splitscreen or singeplayer.
4th. Yes, each file should be under 2KB size, and they should be under 1KB. (they also need to be uder 26KB...). But your codes fit properly in 1KB, so why a '4th'?
5th. Don't you need to put 'set' in front of unlimmited ammo and put set in front of jump height?
And yes your profile gets changed (not your online one), so just make a new account if you don't want to change the settings of the one you are using now.