As far as I understand your post,are you saying the shop owners want to be the models? If so you have the toughest job.A well known photographer said," All models CAN be subjects but not all subjects can be models" for obvious reasons.
I've been reading up on the topic a bit and the biggest challenge I see is making the subject comfortable. Probably not going to be suited for this type of work but I am going to give it a shot anyway.
Making subject comfortable is being confident of your skills and equipment
(not fumbling in front of model) but most importantly is building trust between model and photographer.In otherwords being professional in conduct as photographer vs model (No staring/oggling,touching or making improper comments of course you need to look but assure them it's because you need to see the best angle and what light model looks good in for a certain look).Don't belittle yourself if you put effort you can do it, not a big deal just common sense.
I gather another critical thing is to ask the subject what they see as their best 'assets' and things they'd like to avoid.
Wrong.Never. The women themselves are not the best judge.Only you the photographer seeing through the viewfinder and experience is what matters.Plus good hair stylist and makeup artist.There are other stuff but get the basics right first.
Please understand the difference between boudoir and lingerie.
Boudoir is a genre or type of photography which is ALWAYS about the model or subject or woman.
Lingerie is a product. Technically you are shooting product photography
in a boudoir setting which is akin to fashion photography.One has emphasis on the woman and the other a product.POsing IS different! Just see fashion poses it does not emphasise the model who is only a clothes hanger.
Your biggest challenge is lighting.What kind of ambience do the clients want,
who are the target audience.These are some of the things that you will encounter.
