CNY is expensive enough already, so no need to buy things only to discover later you didn't need them. This I think is the minimal set that will allow you to perform all the 小習い点前.
If I would teach CNY, I would spend some time on teaching how to make 道具 yourself to foster an understanding.
Until the student acquires a quality piece, the teacher should lend a quality-piece to the students. There is really no space in the world for plastic-made 棗 for practise.
Ideally, all 道具 should have meaning, be made by myself; with box and 仕覆 (if used in 茶箱)
Until I'm through with this list, I can't buy new 道具
着物 (which would be a cool project to make myself, navy)
茶巾 (thick type, which ideally is new every time)
2 茶筅: smaller type, so it doesn't look silly next to the smaller 棗 and so you can use it for 茶箱, and a smoked one (for 貴人）(I guess these are hard to make yourself here in CH, due to the lack of aged bamboo, but I have to try; ideally, these are only used a couple of times and then go to the 茶筅-shrine fire) (or do we have some reeds here?)
茶杓 (with 壺, so you can use it in 飾り) (in my case, make one from some Swiss wood)
1 飾り柄杓
茶碗
Black 楽 (can also be used for 筒茶碗)
2 stackable 天目, with 仕覆 for 茶箱 and 飾り; and the large one can be used for 洗い茶巾
Ideally, one of them breaks, so you can add 金継ぎ
天目台 (great wood turning exercise!)
棗: one small black lacquered 棗, which can be used for 茶箱, too; and for 茶通箱 and 包み帛紗. If you end up making it yourself, you can put your 花押（かおう） in the lid!
茶入: one that fits 茶通箱, and ideally has a 仕覆 with a long chord (perfect for me: I can finally make the Kuusama 茶入!)
建水: get one from a bronze 皆具-set, which you will need for 長板 and higher, anyway. This should also have a 蓋置, which ideally isn't made from bamboo so it can be used with 棚. It should be big enough so you can use it for 入子建 (and I'd like it to work also with the 桑小卓（くわ こじょく）
棚
Instead of 棚, get a たんざく-style box, which is much funner
水次 (bentwood)
Instead of 棚, get a 台子 (those are really expensive) get one where the top shelf can be used as a 長板
水指: a 鶴瓶-style 水指; and the one from the 皆具-set (making sure it fits the たんざく-box)
茶箱
Ideally, get one from unfinished wood, with matching boards etc.
ちとせ盆, which is a good storage container and usually comes with a 古帛紗
鉄瓶 (silver would be really nice!)
香合 can be really anything, as long as it comes with a tray. Ideally a bird, to mirror 利休's 瑠璃雀香合（るり すずめ), which goes well with the 鶴瓶水指
One scroll with a seasonally invariant text (great project!) (Could be mukanjo, which is cold in summer, warm in winter and Zen inbetween)
茶壺
花盆 and 花入れ (bamboo)
朝鮮風呂
炭: Get 飾り火箸 from the beginning, and a 箱-style 炭斗, which can be used in both seasons.