It can be pierced anywhere you want
Usually, yes. They just get bumped more and stay cranky longer.
The longer you had jewellery in the piercings, and they have become seasoned piercings (over a year old) then the piercings can remain viable for several weeks (this also depends on the gauge the piercings were done at).
Dermal anchors are not for everyone, unlike body piercing these are implants that are intended to stay in the body. The science of dermal anchoring is still very crude and not very refined, they are prone to infection, rejection and tearing out. In the event you ever with to have them taken out you must see a doctor to have them surgically removed. They can not legally be removed by a body piercer, that would be considered a surgicalprocedure and practicing medicine without a license. Dermal anchors and the installation of the anchors and the use of biopsy punches is illegal in some US states. So check with you local body piercing studio and health inspection unit in regards to the legality for your area. Be aware that some piercing studios will do dermal anchoring when they really don't know what they are doing so be sure you find a studio that has a good reputation for there work. Remember this is not body piercing but body modification and should never be confused with body piercing, this is a totally different ball or wax, you pay your money and take your chances.
It varies person to person. On average, it takes 3-6months for the piercings to heal completely. Everyone is different.
You can get what's called a dermal punch, where they literally punch out a piece of skin, similar to a hole punch that you would use on paper.
Lip piercings if you are following your written aftercare to the letter, should show a decrease in swelling by the two week time period.
Stay as healthy as possible. You can even take Vitamin C supplements. Avoid hitting the piercing and clean it correctly. Of course, some piercings will reject eventually, its just a matter of when. Piercings like hips, wrists, back dimples and some other body piercings reject quickly because of the motion in that area.
Definitely not. Your immune system is already compromised and a piercing will make it worse. Your piercing will take forever to heal if it even does. You'll have a higher risk of getting an infection. Just stay away from piercings until you are 100% better!
Oral piercings are reccomended to stay away from anything dairy or full yeast products like "full rise bread rolls" for the first 2 weeks of piercing. Sandwich bread is ok though.
Well if you have had the piercing done twice before you need to be looking deeper than what type of material you get the piercing done with. Your piercing could be too shallow, you could be reacting to the aftercare product, there can be several reasons your piercings are not "staying". I would have a chat with your body piercer and figure out what the issue is before jumping into the piercing.
Wait at least 2 months before you actually get the piercing wet. Before that, you can swim as long as you dont get your ears wet. Be sure to clean them well afterwards too. Water if filthy, and if you go swimming earlier, you increase the risk of infection.
Stay out of the mosh pit. Only a fool would rush into a mosh pit after stretching piercings, I don't consider you a fool, so stay out until the piercings have settled down ( about 2 weeks or more) .