Can you arrange for a three way phone call or video call if the three of you can't get together soon to discuss things?
If it helps write down your questions and concerns so you can referrence them during the talk rather than depend on your memory (if you have that problem, lol).
Ask her WHAT his communication style is. Odds are she can give you a more comprehensive answer
I've heard of partners sharing information like clothing sizes, favorite colors, food preferrences with other partners, lol.
This can lead to more and more wonderful things as you get further along. Being able to enjoy his primary's company certainly helps things along