- The idea about Mayuri being a disease carrier seems pretty good; the way Sichr has worded it, it would imply that 1) she may have had a kind of contact with a client which went over the boundaries of geisha-hood and 2) well, she is carrying a nasty disease. It's a good trump. But I'm thinking on how to operationalize it:
1 - Feeding the rumor mill is an easy enough way of doing it; but it's time consuming and once the fact is jumpimg from mouth to mouth, we lose control about the dishonor issue;
2 - Creating false evidence of disease could include falsifying medical records or the like; that would involve more legwork from our part and money spending, since not one of our characters is skilled on forgery (okay, the marriage thing could have this problems also, but the way I was planning it, it had no need to).
Feeding the rumor mill would be, like you say, time consuming, well, we may make those people act immediately...
1) we make one of those clients disappear, or at least we create datafile that would tell people that he has been hospitalized...creating such data background may be possible with mouse and fractals efforts...
2) we immediately after this begin to call others from the list, asking them for symptoms. They would possibly give us the answer, possibly not, well alarmed, they may have call their own medic assistant to get some care. Good, this is bonus, our work will cause some income in pockets of a few doctors

3) It is possible that some kind of lead would slip from us during the call, implying that amongst other things those guys from the list have in common is some geisha...not necessarily she is the source of infection, well, we need to check every posible track
4) It may drop into right ear, and some of those guys check the information with the teahouse.
5) Such possibility would be disaster, so I can see that teahouse doctor is on his way there after second/third call...or Mayuri in limo on her way to the doctor (maybe even better)
6) We need to know if they have medic using magic (well since they are Yaks...) if yes,, it would be more difficult to "Influence" If they have doctor who is using technology for diagostics...well...I guess that he would get whatever reading we would like to give him.
7) Only...we need to chose good ilness, so they dont put the bullet to her brain to get some kind of bounty...

Well, this can be our Plan B, we better have more options

P.S.: This is second best use of nanotatoo: some kind of eczema .. symptoms...