Seeing apps on multiple iPhones
Yes - deleting an app from any device will not remove it from other devices.

Only if you:


Delete the app from iTunes
Sync more than one device to iTunes
Bypass the warning that an app is present on the device but not iTunes and skip the chance to import that app back into iTunes


will the deletion of an app in one place cascade over to other devices. You might also want to review which devices automatically download apps so that you don't get apps that are purchased and intended for another device.