yes - go ahead and set it up for gain=1 voltage follower, and apply voltage steps to the + input. your DC condition should be satisfied by the fact that it's a follower. 1v-2v steps may be better just to keep it away from the bottom rail - maybe your amp saturates at low Vout, so a 1.5v common mode like this may be better.
you should get an idea of the phase margin from looking at oscilloscope response to the voltage steps , just viewing the settling time characteristics. it's crude, but without a network analyzer it's the best way i think.
to calcualte gain, set it up for a few different DC gains, maybe 10, 100, and 1000. now apply test voltages of 10mv, 100mv, 1v to the noninverting input. you can calculate the gain based on how well the output followed. if you need a better example i can try to set one up in spice in the next few days.
make sure not to load down your amp - using 1Ohm and 100Ohm for gain=100 isn't going to work well unless you have a really powerful amp. on the other side, remember that bjt have input bias current so for 100nA Ib you get 1mV offset for 100k resistor. CMOS does not have this problem so 10k-100k is a good range..
you'll need to hand-pick or match your resistors as precision is the key here. use the true measured value of the resistors when calculating.
read through this link, which is a good explanation too
**broken link removed**
other than that - i think you have it!