It has No importance

No

It should only be placed here, because this way the circular amplification is high

Yes

With the difference between the outgoing and incoming signal

With the reciprocal of the gain 

By the reciprocal of the transfer of the feedback network

With the reciprocal of loop gain

By the square of the quotient of the outgoing and incoming signal

a few Hz

No limit, infinite frequency

a few kHz

a few MHz

Uin associated to Uout zero

Uout associated to Uin zero 

Offset of the frequency plot

Due to saturation of the output transistors

Because of the final output current level

Due to the limited output current or voltage

Because of the power supply voltage level

If the feedback gain increases, the bandwidth increases

No influence

It depends only on the feedback network 

If the feedback gain increases, the bandwidth decreases