Questions I would ask:
(1) List of degrees and certifications. For example, is the practitioner certified in NPR? Not only is she currently certified, but how many times has she actually performed the neonatal res. in an urgent situation? Experience being, of course, different than book learning alone.
(2) Status of licensure. Is she legal or illegal in her state? Don't let her escape into some sort of alegal claim (alegal is illegal). Has she had her license removed or suspended at any time by any state (including her current state)? This has been an issue, for example, where a practitioner who had her license removed in Minnesota was able to obtain a license without difficulty in Oregon. What were the circumstances of any license removal or suspension? Has she had to appear before the applicable State Medical Board or State Board of Midwifery? What were the circumstances and outcome of such appearance? I would search the records of the applicable State Board to verify license status and history.
(3) Has she been charged and/or convicted of any crime (beyond simple traffic violations)?
(4) Has she been sued in connection with her practice? What were the circumstances of the suit? I would also make a search for her name in local court records to verify.
(5) How many babies has she delivered over what period of time? How many sets of twins? How recent is her twin experience? What was the birth positioning of the twins she has cared for? What sort of positioning would risk you out of homebirth (breech-breech, for example)? What is her outcome over the life of her career -- in terms of babies with morbidities (NICU stays) and mortalities (death of baby or mother)?
(6) What sort of testing will be performed? GD, GBS, all standard tests, etc.? How frequently will the twins be checked by ultrasound (to confirm that they are growing concordantly, etc.)? Who will be performing the tests (if your practioner is a midwife and unable to provide these services)? What test results will risk you out of a homebirth?
(7) What sort of drugs and equipment is the midwife bringing with her to the birth? Is her possession of those drugs legal or illegal? Twin moms have a higher risk of post-partum hemmorhage, so I would be especially concerned about her ability to carry the drugs that are used to treat PPH.
(8) What is her experience with emergency scenarios? Does she have actual experience treating PPH or has she just been lucky so far? Has she handled SD? Has she ever cut an epis? What is her experience with reviving flat/blue infants? What were the outcomes of her handling of those emergencies?
(9) I would try and see if I could get any info about her from the L&D department where she usually transfers. I have a L&D nurse friend and she says that some midwives can reliably be counted upon to wait until the mother reaches trainwreck status before transfering while others transfer in a timely manner before the trainwreck happens.
(10) Does she carry malpractice insurance? If not why not?