yeah you won't be able to understand hegel. to be honest even if you think you understand kant you probably don't (unless you're just reading ethics).
tbh i don't understand why everyone gets so excited by the idea of reading primary texts for this sort of thing, unless you think it's just a signalling effect. you will not be asked about a list of books you have provided, so it is much better to read more contemporary stuff which will make you better at answering questions (especially if your intention is to do well in the interview, rather than just get smarter)
almost everything you've referred to is really old, anyway.