First of all I think the first 3 cars are well matched and make sense ( decent space via rear seat or hatched rear, relatively evenly matched power, smaller stature)
#4 seems a bit put of place from the above points as well as it's the only one with a v8, totally different character.
Regardless my thoughts below On the respective #'ed car
1). 235i; overall great car, amazing power (torque=king), style, and handling are superb. Dont bother with the 4cy turbo, drive them and you'll know why.
2) tt is a great car and will be a tank in the winter, but won't have the power feeling of the 235
3) z is a great car, no big complaints except that it's not as tunable as 235.
4). Not for me, but great bang for the buck. I'd rather have a used e92 m3.
I'd pick the 235 or tt rs (if that was a choice)
(for reference it seems like u have some well balanced options around 40k, good choices, but I think the c7 doesn't fit