"Also, do some research into transfer rates with various MWs (especially for 1st time mothers!) and c-section rates for HBs. Look into what sorts of client care your local midwives offer -- can they give IV fluids, postpartum hemorrhage meds, oxygen and etc. Look into neonatal care safety."
I agree with IdentityCrisisMama that whatever midwife you pick should have a significant transfer rate for first time mothers. I believe the Birthplace Study out of the UK had at least a 20% transfer rate for first time homebirth mothers and that study included only the lowest of the low risk with college educated midwives attending.
I would also agree that, in addition to what IdentityCrisisMama says, you should know her:
(a) education, (b) license status, (c) malpractice insurance status, (c) length of practice, (d) number of babies delivered (this is important as a midwife may have been practicing a long time but be a "hobbyist" (for example, only taking on one birth or less a month) and this means that there are any number of complications she may not have seen in her practice despite being a midwife for a long time), (e) what emergency situations she has experienced, how recently and how she handled them (shoulder dystocia, post-partum hemorrhage, neo-natal resuscitation, etc.), (f) whether she has been charged with a crime or sued or lost her license in any other state, (g) number of stillbirths or major morbidities (like cerebral palsy) for babies and mothers under her care, (h) how many births she has missed (by being too late to arrive) and (i) birth philosophy (a "trust birther"/a "med"wife).
A friend had some luck interviewing midwives by asking each of them which midwife they would want to attend their own births. It became pretty obvious which two local midwives were not thought well of by their peers.
However, I would suggest that, in interviewing your midwife you need to acknowledge what you don't know. In other words, there is no way you can meaningfully evaluate whether your midwife knows the proper technique to resuscitate your newborn, can do a complete newborn exam or properly evaluate whether your tearing needs suturing and suture it appropriately.