Oooft I'm having some fun with SA and HSBC. I can see an SA ID on my HSBC statement. I don't recall enrolling directly. I tried to reset my password and failed, so got in touch with SA. I must say they have been quite helpful and quick to respond to multiple emails. Anyway, they told me this:
"we noticed that you reached the eligible spend for the welcome offer on January 23, but we were unable to send you a notification because you had not yet activated your account" (Makes sense as I never received an email of course and know nothing yet. HSBC haven't been helpful either),
and
"Please be informed that the name in your Star Alliance Rewards account must match the name on your preferred frequent flyer program, otherwise, the upgrade request and points transfer may fail."
So, SA only use First Name field and Last Name. I took a look at Aeroplan, they have First Name, Middle Name (optional), Last Name.
SA want to know if I want to set First Name to my first middle or simply my first. Geeze, I've got no idea really. Anyway, sent them a screen shot of the Aeroplan proposed set-up and asked them.
EDIT: SA responded and advised me to set Aeroplan's First Name field to both my first and middle names. Interesting.