Feedback Amplifier Analysis (more :) ) - again solution provided, need conceptul help

Solution is provided (those in part (a) it says series-shunt which is incorrect, it should say shunt-series). Looking for conceptul explanations. In part (e) when the gain is being calculated, why is the 2k (Is resistance) not being included? how would i know when / when not to include it? Also, got vo/vo1 is this a universal way to calculate the gain of a BJT? (collector/emitter)? and why/how is it negative?

For part (d), what is the process one uses to calculate I`f/I`o. Is it the same as for Vf/Vo? ie. take all the resistances in parallel with the voltage and if there is some in series, you divide all of them in parallel by all of them in parallel plus the ones in series?

Explanation in simple, easy to understand terms please! :)