@mikejungle
Welcome to BNut, if you stick with through the first few disasters that we all had when we started, you will have started a great, life long hobby.
I live in Zion, just north of Waukegan, east of Gurnee, so I am probably less than 20 miles from you. I don't want to be ''Debbie Downer'' but your trees have a less than auspicious chance of getting through this winter. As Peter Tea said to me and the rest of the AAC, ''if Californians had to do what we have to do to get through our winters, nobody in California would raise bonsai". The Chicagoland climate is brutal.
But I will help you the best I can to figure out something to give your trees a the best chance of survival. Each of your trees have fairly different growth habits. But all need a winter dormancy. A key point, that took me years to finally believe it is a ''good enough to be useful approximation'' is that if you keep the temperature below 40 F, for all intents and purposes the metabolism of the trees is so slow that they can be stored in the dark. Believe me, it is true. Your pines and sequoia will be fine if you put them in the garage if you can keep the garage below 40 F. At this point a cheap thermometer is a good investment. Put it next to your trees. Jot down your temperatures so you don't forget. Check mid day, to see the high temp and late night or early morning to see the low. Even if this batch of trees perish, the temperature data will help you next year when trying to figure out where to keep your trees. Also be concious that the outside wall will be colder than the wall against the house. Get data on both areas, choose the one that stays below 40 F. Because you repotted so recently the garage is the only option. Next year the bristlecone should be outside, and sequoia will need the garage. We'll talk about the black pine, but probably it will need the garage.
Perfect storage temperature would be below 40 F and for freshly repotted trees above 28 F. Above 32 would be ideal, but as long as you keep the garage above 23 F all winter they should all be okay even though they were freshly repotted.
Soil - from the sounds of it, your soil mix basically is good. You got the idea. I would have skipped the cactus mix for the bristlecone pine, but this is not a serious issue. I would not change it. The sifting to remove fines is the key to making any potting mix perform better.
IF at all possible, do not repot any of the trees for 2 growing seasons. They need to get some growth and recovery time. Bare root shipping an repotting is quite traumatic. Contact me via PM (private message through BNut) and I will make sure you get some inexpensive pumice & other ingredients to add to your potting mixes in the future.
Watering - the best water meter is the human finger. Dig in at least the full depth of your fingernail, use this to ''calibrate'' the bamboo skewer system by comparing to the look of the skewer. If your plant collection is small, just hefting the pots you will know by the weight whether they are wet or dry. Use your finger to calibrate your sense of heft. After some experience, just tilting the pot a little, the weight will let you know where you are at. Water quality of Chicagoland ''Lake Michigan'' tap water is excellent, good for most species, most genera. Lake Michigan water is about 180 ppm Total Alkalinity as Calcium Carbonate, and the total dissolved solids are about 225 to 240 ppm by weight. Jot this down, you may never need to know it but when you do need it, you got it. Medium hardness. Well water in the northeaster Illinois area tends to run 600 to 1000 ppm total dissolved solids depending on how deep the well is. This would be considered hard water, and could cause problems for some species. With well water you would be best using collected rain water as often as you could. Though well water is better than no water or purchased bottled water. Water twice with rain water, once with well water is an okay plan if summer is too dry to collect enough rain water for all the watering. Lake Michigan tap water is good enough I don't bother collecting rain water. ''Another useful approximation''.
Fertilizer - you are correct, your trees will not need fertilizer until spring. Mira-acid, Miracle grow are great as soluble fertilizers. Osmocote - it is something I have used, but there are some tricks to using it. We can talk about this later. Keep it, if is already on your shelf. Some recommend organic fertilizer, I personally prefer the inorganic water soluble. There is no right or wrong here, just different techniques. The best thing about soluble inorganic fertilizers is that you can precisely control the timing of fertilizer applications. The MSU formulations of inorganic fertilizers are far superior in terms of total nutrition to any organic and the majority of brand name fertilizers. Again, more later, got all winter to chew over this topic.
Brown needles - don't worry. most likely normal. If they fall off easy just pick off and discard. Leave if they don't pull away easy. Sequoia may or could turn a bronze color for the winter. The bristlecone might also. This is normal. Some trees have a dramatic color color change to their needles, some don't. Some junipers turn purple, some stay green. It varies. Because of the color change if the needles don't easily pull off just leave them, it could be normal winter bronze color.
Shaping - not now. Never wire a tree AFTER repotting. The tree needs to get re-established and roots need to firm the tree up in the pot. The jostling of wiring can break brand new root tips setting the tree back further. So no wiring now. Probably late summer, or autumn, or early winter 2019 will be the first time you want to wire or even begin to consider shaping. Often wiring, shaping, pruning can be done just before repotting. This varies depending on the health of the tree.
Okay, enough for one post. I'm going to pour myself a cup of coffee, and I get back later to you on your species choices.
. However none just repotted!
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