Everything you do with Meredith affects her outcome, what and how you react to Tommy affects her outcome. From what I understand, you can fail recruiting Meredith (Game over?), but I don't know for sure. Telling Tommy to be truthful is one way to make it harder on you. I do know you can make some pretty bad choices that do not let her advance (gain aff or corr). Even says you can scare her off. But like I said can you really fail? No idea...
You are full tilt corruption/affection (mine is balanced) on Meredith, what you do affects her attraction for you (lust) or corruption (desire) for you, basically how she see you.
You're right about the interactions between Meredith and Tommy not being the same. Remember what happened at the hotel, it changed everything for Meredith and that simple fact is reiterated at the start of the chapter with her and Red. He even point out they no longer need to be in front of the camera anymore. It's meant to have a profound impact on how she feels about Red, it was the one thing she said no too and then she does it herself anyway.
I don't know for sure, but I think this will have an affect on how she interacts with you. I asked on Patreon what the different paths mean, but to be honest the Dev never responded. Some clarification in game about what these different paths mean would be nice.
Maxime is not really in the picture for the most part right now, the story is about Meredith currently. Maxime shows you what she is about by helping Red with everything, she is 100% devoted to him. As was said by Julia, she's coming back and will probably never leave Red's side again. I think Maxime will grow once this Meredith thing is over. I am interest who his next woman will be, I expect more.
The whole point of Julia and Ruby and why that is still shown is to show how much stronger he has gotten. Julia tells him she can't handle him any more, he's gotten to strong. She the lets Ruby take over in his weakened state to see how much farther he can go, Julia even says Ruby is much stronger than her.
It was mentioned several times, he has to learn to resist, that if he can't he will die and it only take a touch to do it. This is the reason for the training along side showing his growth.
The bra thing was discussed on Patreon by a few of us. It didn't make a whole lot of sense, but it isn't unheard of. The Dev might find that kind of thing to their liking and that is why it's that way. It's different, so there is that going for it, not many VNs have women leave their top on while having sex. Different is a good thing sometimes.
Brie has a whole other problem, she was also abused by his mother and has scars like him (not as bad). I, and this is my opinion, think her power is being blocked off. This has caused her to slowly lose emotions, she even mentions it's not just one emotion she can feel others dulling too. My guess is Red will have to make a pact with her to break this seal. I'm going to go out on a limb and say his mother did it to her based on what she told Red his mother did to her.
Red knows he can affect her with his power, but it's not enough to get through, this is my reasoning of it needing to be a pact.
The update wasn't that confusing to me, here is how I looked at it and what I took away from it.
It showed how close Meredith is to breaking and what a stupid ass Tommy is.
It showed how much more powerful he has gotten based on his interactions with Julia and Ruby.
It brought Brie into the picture with her problem, he now has to figure out to save her from her fate. This gives the story something else to focus on beside corrupting women.
It let us know that his mom is no one to be messed with and everyone is afraid of her.