You have a pretty good list right off the bat. I'm going to start by commenting on your current list before suggesting new stuff. A lot of my suggestions will be around maximising the #of games off amount of $:

*I personally hate it, but 7 tons of people love 7 wonders and it easily scales up players without a lot of downtime. *if you go with 7 wonders, skip sushi go. Both utilize the same mechanics, though 7 wonders plays a larger group and is a bit broader. Sushi go is cheaper though and will get you more games *TTR Europe is my recommendation over the two options. *Carcassonne strikes me as a standard to a collection. Good recognizable gateway. Start with just the base for now. *pandemic or alternatively forbidden island/desert are good choices *dominion is difficult to recommend as it then opens up the question of "which expansions" and so on. If your purpose is to build a large collection, stick with just the base. Otherwise, add maybe seaside/intrigue *codenames is a great party game and the simplicity of the game you could maybe get away with a decent PnP if you can use your school's printer. There are some DIY templates on BGG. *stone age always struck me as lacking as a worker placement. I'd recommend viticulture. Other choices would be agricola, lords of waterdeep, or champions of migard. *key flower is out of print right now and as a result expensive. I'd avoid for the moment *coup/avalon/werewolf are great, cheap games that scale up well. Definitely get one of them, but no more than 2. *highly recommend splendor, see if you could get it on sale at target or something if you have them near you. *if you get a tiny epic game, go with galaxies.

Other games you've mentioned I haven't played and can't comment on. I'd also recommend mysterium, betrayal at house on the hill, bang the dice game or some variant.