You can but the balls on barbells are usually huge and will look strange in a nostril piercing.
No, tongue rings are specifically designed for tongue piercings and are not suitable for an industrial piercing. An industrial piercing typically requires a long straight barbell that goes through two separate ear piercings. It is best to use jewelry that is specifically designed for an industrial piercing to ensure proper healing and comfort.
It might be. If you put in a barbell that is a smaller gauge than your piercing, then it is a possiblity (depending on how old the piercing is) that it may shrink down to the size of the gauge you have in it.
Put a shorter barbell in the piercing and it won't look crooked.
Peircing you right nostril
Well if you still have the barbell and you can get it back in the piercing without damaging the piercing, then put it in and tape it down till you can get thread on balls for the ends. If you think you have issues of not being able to get the barbell back in go see your local body piercer and have them put it in for you. They can taper the piercing and put the barbell back in without damaging the piercing.
None....... It's a straight line piercing the curved barbell will actually irritate the piercing.
You can keep your navel piercing until you start to show, then see your local piercer and get a flexable barbell put into the piercing. It's call a PTFE barbell and it will allow for the piercing to stretch without tearing the piercing. However be sure you are getting a PTFE barbell and not some other material. PTFE is biocompatable and will be accepted by the body without issues, I have used these for hundreds of my clients without problems.
A nostril piercing will look like a nostril piercing the next day, there may be some light redness but this will ease off during the healing period.
The barbell is too long for the piercing and should have been shortened after two weeks, get a shorter barbell in the piercing and it should settle down.
If we are talking about an industrial piercing, yes you need two piercings. however you can still wear a barbell in one piercing provided that it is fitted to work in that single piercing.
You don't put a back on a regular stud in your nose! What you do is get a proper nostril screw stud for a nostril piercing and put that in instead of the ear stud you have in your nose. If the backing comes off the regular stud in your nose and it is inhailed it can go into your lungs and then you have some serious medical issues.
barbell is better because if you get a ring it rotates around and the bacteria gets inside the piercing also if you get it pierced with a ring you might have difficulty putting a barbell in later