For Waltzes, most of them are doable.
I haven't heard of a Waltz in C Minor by Chopin but perhaps you're talking about the C-Sharp Minor Op.64 No.2?
Some doable ones are Op.34 No.2, Anything from Op.64, Op.70 has some nice ones, if you wanto to go for the more challenging, then the Op.34 No.1 and Op.18 are also quite fun. Op.42 is a bit on the harder side though based on the two pieces you listed.