I don't know any older INFJ's (except my mom who is a bad example).. but my boss is 40. Could this outdoor-physical engagement-gambling be the development of inferior Se? Is that typical?
Sure! - although I can't relate to the partying or gambling bit. (like boardgames/mindless games like Mahjonng, however
) (For my part, I've never really viewed tertiary or inferior functions as a bad thing.. and also I don't think the 'development' has to follow any specific timeline. I think there can be elements of all throughout ones' life.)
I think INxJ's will always have that Ni preference / cerebral focus and mindset - I mean, that will never go away - but I think it's actually quite common for INxJ's to engage in hobbies in their free time that are very physical/Se-ish in nature, and to really enjoy that and get a lot out of it.
For myself, I think a lot of my hobbies have always been rather Se-ish in nature, and that began as a child. My interest in nature/the outdoors began at that time. But, the WAY I approach it - the way I engage in these activities/view all of it - is quite possibly pretty different from how an SP would; we both may be doing the same thing, but we do it for different reasons, get different things out of it maybe, etc etc.
So, yeah.. I do the outdoor and rockclimbing thing. Both of my INFJ friends enjoy similar things, and one during her free time spends a LOT of time training for triathlons, marathons, recently joined a weekly volleyball clinic.... Important to keep in mind though that we're all still very much 'cerebral'/theoretical... our hobbies might just allow for us to take a break from all of that and balance ourselves out - and get a bonus rush out of doing so.
Regarding your boss wanting the 'facts and figures' - it could easily just tie to 'wanting to get to the point/heart of the matter' early on - an effort to hone in on what she views as key areas to focus on / that will help her to better see the big picture. Without much more detail, that's my only guess.
Edit: btw, didn't really read the entire OP.. just the first paragraph ..but specifically wanted to addres your question re. Se-type interests.