If your phone is powered off or in airplane mode it is not supposed to emit RF and thus cannot be tracked. This is a matter of trust, so if your threat model includes high end threats, the assumption that it follows the normal requirements may be invalid.
If you remove the battery, it will be unpowered and unable to emit RF and thus cannot be tracked. While it is theoretically possible to hide an auxiliary battery in your phone, that would be very hard to achieve, especially in modern thin phones. If your threat model includes highly motivated state sponsored actors, this is could be achieved.
If you put your phone in a RF-tight enclosure (e.g. metal box), the RF energy cannot get out and thus it cannot be tracked.
The bag is only going to attenuate any signal, not block it (block would imply infinite attenuation). Whether or not the attenuation provided is sufficient to prevent an adversary from receiving the signal I'm not sure. I definitely wouldn't bet my life on it. I'd want a pretty thick metal box with proper seam gaskets as a minimum.
Yes, if you're in a city you're tracked constantly by dragnet surveillance.
Questions like this one aren't very useful without a threat model. Who are you trying to prevent tracking you? If it's just your phone carrier then obviously turning off your phone and removing the battery will render it inoperable. But now you don't have a phone, and your location info wasn't very useful to begin with anyway unless you were involved in an operation where you need to conceal your location.
This goes into I Don't Know What I Don't Know Dept. (sorry Mad magazine)
A patron was telling me that the way the GPS is so accurate is because it uses the phones radio... Didnt know that either. (i mentioned to him that there is one spot in MA where our google directions are off by 1/2 mile.. Same place every trip.)
If you remove the battery, it will be unpowered and unable to emit RF and thus cannot be tracked. While it is theoretically possible to hide an auxiliary battery in your phone, that would be very hard to achieve, especially in modern thin phones. If your threat model includes highly motivated state sponsored actors, this is could be achieved.
If you put your phone in a RF-tight enclosure (e.g. metal box), the RF energy cannot get out and thus it cannot be tracked.