Can anyone explain the difference between these words? They all basically mean "to set up / to found", and from what I've researched, it's all very 微妙 to me.
そうりつ「創立」 is used for foundation/establishment of buildings (refer to physical items, have some sense about first time establishment one's life or pioneer alike)
せつりつ「設立」 is used for foundation/establishment of organized associations (kind of logically, general word)
設立 is more general word, so it would be used for those kind of foundation stuff, and there is another word 「創設」, which is combination of above two kanjis, and make 創設 and 設立 more close when related to company.
Note: But why I used "refer to physical items" for 創設 is, it suppose to be point to physically visible building, but for "associations", main point is not about assciations's building, but refer to logically grouped one.
じゅりつ「樹立」 is used for foundation/establishment of new goverment, parties, records (similar to 設立 but only for special things)