How lenient is this game with S-Links and maxing them all? I remember Persona 3 leaving you absolutely no room for error, and I'm afraid that I may have already mucked it up by missing the opportunity to open Ai's S-Link...
 
Also, what tangible benefit do the side-meetings offer (i.e. when someone calls you to hang out on a Sunday)? I have never gotten a rank-up from them yet. Likewise with the matching Personas; trying to wing this one, I haven't been matching my Personas to the S-Link yet I'm still thus far ranking up once every "date"?

I'm not one hundred percent on all of the p4 mechanics, but I know that the "side-meetings" give you more "points" towards your next rank-up; reducing the chance that a regular meeting will just become "you spent time with X..." with no rank-ups. Matching personae to your dates helps by giving you more points, the same way that some answers give more points towards the rank-ups. 
Though I'm more involved with the P3 mechanics, so feel free to correct me if I've gotten things confused...
 
Oh, and I have no scientific basis for this, but from what I've seen and played, P4 was much more lenient compared to P3, but I'm not sure how much room for error there is...

http://www.gamefaqs.com/ps2/945498-shin-megami-tensei-persona-4/faqs/55038

...was thinking of recommending gamefaqs (or similar), but at the same time I know that I, and probably other players as well, like to keep away from them; once you start looking it's hard to stop reading and ruining the challenges for yourself.
 
...But I guess that could be just me as well...

Mmm, I didn't follow a guide and managed to max everything except for the Student Council one (which was rank 9 before the endgame), so I think I'll just wing it if you guys say it's more lenient. Maybe make decisions as I would in real life.
 
If I can get Yumi and Yukiko, it's good enough for me.

" @Hailinel:  You have got to be shittin' me. I've been trying to focus on Yumi and Yousuke... So I should have invested my time into Chie instead? FFFFUUU... Well, at least I'm only in mid-May. "