Boiler connexion => nice, that will help some players for controlling precisely their nuclear power plant in case reading their temperature was not enough x)
Also yes, it is beautiful , it looks like heat distort the view like over asphalt or hot sand, cool trick i'm going to try and mimick whenever i can now x)
Landmines => wait what ? if the middle mine blow up, doesn't that cut the signal that could cross over a line of mine ? does the exploded mine emit the signals ? does the absence of the signal prevent the mine from firing up ? like the mine is disabled ? are biters going to ignore it otherwise ? You already answered the most important question about friendly fire but some points remains unclear
Self subtraction => That must have been a difficult decision to take, one that breaks existing setup, it looks a bit puzzling to see all the new UI options but it makes sense quickly, chest being the easiest to understand for me intuitively, and trains stop the worst. "Read train count" there's no room for it but "broadcast incoming train count" would make it easier to understand why we choose a wire for the output and that we choose the signals for this. I like the agritower having more options for circuits too, but it appears that you still can't output on different wire color for biochambers, wether the "quality nutrients" are in the "fuel" or in the "ingredient" slot and i feel someone will mention that at some point because it was suggested that there be "more straightforward method" to deal with that particular niche case, choosing which wire color to ouput things onto could have been a solution

, Also i was expecting a picture of asteroid collectors there, it will be a surprise then ^^ Overall i think it really adds a nice layer to the circuits capabilities and i like it.
Automatic lab research => That's nice ! It gives much more flexibility to Gleba inter planetary logistic, even less excuses for overproducing now !! It's done without using new signal per research, it's going to make it harder to use speaker to announce the tech that was just researched , but it's probably better for the RAM which is costly nowadays
cargo bay extension => That's cheating ! if it didn't look so good i wouldn't use this. I like the part for elevated trains, having them drive in weird direction over nicely ordered solar array is one of my favourite view of factorio, particularly when there's no gap, that's what i will try to use first. Also why not 60 ??? why 59 ??? it's like you open your chocolate bar, and there's that 1 piece crooked , poorly melted or already biten and you don't know what happens and it's going to haunt you forever !!!! ( /not-so-serious)
Planet visibility => Waow ! That's so cool, honest to recognize the modders contribution, and the whole rotation thing ? waow it's beyond what modders could do before but it's still moddable ! that's awesome !! That also happen to be exactly what i'm trying to learn how to do for a pet project inspired by the galaxy map, like at strong zoom, you'd see the planets, experimenting with spitesheet , with lowpoly canvas rendering, with webGL and webGPU for the very reason that were mentionned, too many sprites required for smooth rotation x) The planets themselves looks very nice, and Fulgora with the lightning being actually only on the "dark side" of the planet is such a nice detail !! Now i want to try and learn how to make one in the factorio game x) That's extending the potential fun i can have with the game by quite a lot considering the time it could take me to make it work, but now i can never be bored before it's done x)
Pumps => the dream comes true x) It should never have been illegal in the first place !! Except the one where two trains with the wagon in front can exchange when facing each other, this one is cursed. It look like ants sharing food though. So it's like barely legal x) Can you reverse the direction of the pump with wire ?

sorry sorry
Refinery rework => you won't get me confused there, i can follow the green rusty tank, it's always an output and in the corner with the flare stack , the trick only works when you try to hide something underneath. Although it looks nice without the icons in front, i wont be distracted !!
Assembly machine reworks => ah for some reason i feel the bottom right corner should be more in the bottom right ,on the right side the vertical seem like it's not vertical but going a bit to the "right" where i would have seen it be sligthy toward the "left", on the assembly 2 compared to the 1. Where the 3 is the one that works best for me. Although the pipes are hiding the animated shadows. I really like the animating parts, i feel it's making the most of "sprite sheets" to really show intricate and realistic animation , the kind for which there's no shortcut, like AIs or approximations. It really shows "the work", it looks like better than some remastered AAA games with much more (advertising) budget. Being able to spend so much time iterating and improving on the same engine instead of having a "new" version every couple years where people try to reinvent the wheel, i feel really leaves a very high quality product for a cheap price in the market, polished like it's there to stand the test of time
That's a lof of things for a FFF, i feel 2.1 is getting closer and closer, and applying a regression based on the amount of things i have to do IRL that disctract me from playing, my bet is a release in mid july, or early september. Maybe a bit later, to mark the second anniversary of the release too ! Very bad timing anyway, i wil have to wait until winter for all the fun

Now i wish the FFF are planned for at least 3 or 4 months with some more technical details x)