All true, but worth nothing that Italian-made Dior Monsieur is (often? always?) by Corneliani, so usually worth picking up.
The only Dior that is worth picking up is Dior Homme. If it's Christian Dior Monsieur (usually made in the USA), it is best left avoided. RLPL is top notch. Gant, as a recent brand, has reinvented itself quite nicely. However the older stuff is all over the place and not really worth picking up, imo. RL polos are a staple type item for a lot of folks and you'll see them at almost every thrift store in the US. I don't pick up Le Tigre, but the stuff seems to be of ok quality. Levis is Levis, dependable enough clothing. The only thing that you have that is flippable is most likely the RLPL shirt. However, if the stuff you picked up fits you well and you are happy with it, I think you did ok.