Hi,
lets try to get through it.

1. Why would you change it, you would always "reveal" your public IP adress any time you send out a hash or do anything on the internet. A good Firewall (like a decent router has) is protection enough. Don't use standard ports when you connect from remote or even better use a vpn to connect to it. If you have no inbound traffic, just block anything incoming.

It is not possible to know the exact location of your farm. Only where the Point Of Presence with your ISP is (depends on there infrastructure, might be the first switch in your street or the main switch at the backbone)

When you have a firewall I don't see so much danger. But it's always a good idea to get a professional looking at it. (or reading through the internet if you want to learn for yourself.)

As long as your farm has no insecure inputs, you are safe for the most part. I'd need to know the complete structure of your miner network setup to tell you an my assumption, that is not enough information.

2 depends on your definition on position. In the physical world (see above) no, in the internet your public IP won't be a secret for long :-) It sounds a bit linke you don't understand how the net works (no offence)

Ask away.