weird mix of sororities after first round

This is just more proof that tiers on this site are stupid. Every chapter has certain types of girls they go for. Im assuming the 2 "bottom" chapters you got invited to are the 2 newest chapters, both of which are for some reason hated on this website but def not bot irl which is why they are probably going for you too. My advice is to go into all the houses with an open mind. Form your own opinions. Find the people you click best with and the house your values seem to align with. Only you can decide the best house for you. Good luck.

I stole this from another very similar post since I think it applies to you too:

Every chapter has different things they look for in PNMs regardless of tier. Perhaps you're really pretty but your extracurriculars, gpa, or conversations just sucked. The top houses saw something they wanted and the middle tiers liked other people better. Focus on the houses you have left and stop worrying about tiers, they really mean absolutely nothing (obviously, other than being a beauty competition maybe). Go into EVERY house with an open mind (including so called "bot" houses) and form your own opinions. You're trying to find the house YOU click with and will fit in best with. Dont worry about who everyone else says is hotter (literally all tier is). Worry about who your bridesmaids are going to be, who you'll be netflix and stuffing your face with, or applying make up for days to go party with. Find your people to do what you like to do with.