You're still right, though - talking about closest planet on average isn't very useful, because it's always going to be the closest planet to the sun. Asking "what planet can get closest to some [Planet]" is more interesting and enlightening.
Oof, yeah, plague is a nasty one to start off with. Generally the very first "mission" I do after setting up survival essentials is kill and butcher a couple of big animals, then try to sell the meat and leather for penoxycycline at the nearest friendly base. If I can get enough, everyone gets, otherwise it's just my doctors' drug policy until I've got a steady supply.
Oh, it's a mod, Favourites, https://steamcommunity.com/sharedfiles/filedetails/?id=2720562164. It basically lets you manually tag any object in the game with little stars or trash cans.
Basically, whenever a big raid comes in, I use the Numbers mod (with traits coloured extension) to select who I want to recruit, then tag them with the Favourites mod so that I know to hit them with a shock lance.
Similar process but different star for enemies with nice armour or bionics, or ones with superweapons or low shield packs so that I know who to kill first.

After beating up my kid, these guys are breaking back into their prison


Guess they didn't want to face the muffalo police.
Honestly, I find it to be something of an undercooked feature, and hope that the world outside one's home tile gets built up a bit in a future update.
You can settle new tiles for: Getting away from a threat that's too big. Infestations are a common cause for this. Cheesing resources - You can quickly grab up all the gold and silver of a map before leaving and settling a new tile. Sell at neutral bases for shock lances, horses, and food. Tomb raiding - Crack open those ancient dangers to very quickly level up your weapons and armour, as well as a consistent source of prisoners and bionics.
So new tiles can trivialise the early game gearing up and recruiting process, and at this stage there's basically no consequence to it, since each tile gives you some grace time to settle. To a lesser extent it trivialises the mid-game rush for steel, because why scan when you can go to one of the 6 adjacent tiles and load up a herd of muffalo?
So all in all I feel like settling new tiles is OP in a broken way, and I'd like to see some more consequences. Ideally, threats should be based on faction wealth, not colony wealth, and start appearing after game start, not tile settled, and some threat types should be able to chase your caravan on the world map.
Gosh, that's a lot of landmines! As others have said, you can "encourage" raiders to step on them by putting concrete underneath them so they're more likely to path towards them. You could probably do the same with wood fences to give them the idea of having cover where they might want to try and shoot you, but no, it's just another landmine.
Grab that stray unstable power core, those things are excellent for setting up isolated micro-grids for things like ambrosia greenhouses and deep drill stations. Or just add to your main grid.
You can get rid of your bedroom corners on the inside of your insulation corridor and move heaters and lamps into the space to save on movement costs.
Is the fence there to keep animals out of your minefield? If so, you could replace the sandbags with barricades and get rid of it, because barricades do that job too. And can be upgraded to plasteel as the game goes on.
Shelves to either side of your workbenches' sitting spots loaded up with the most commonly used ingredients saves a lot of hauling time, especially for things like meals and drugs.
I'd maybe think about moving the hospital closer to the psychic emanator. Rooms don't get quite as much advantage with it, and it really shines after a raid when half your colony is in the medbay.
All in all, though, it's a pretty solid looking colony. Good job.
Depends how far back you go. Obvs, not all mods are keeping up as the game updates, but if anything, I find that the modding community has only every grown and gotten better with time.
I think that mod versioning was introduced in 1.1 (so about when Royalty released), which made it a lot easier to keep track of what works and what doesn't, so you might have issues with mods from before then, but honestly there'll almost certainly be a replacement if something was popular and was discontinued.