Hello, here are some pieces that are incredibly, outrageously inappropriate for what you are looking for and/or your skill level at the moment:
Alkan
Allegro Barbaro, Etudes Op. 18, 2nd and 3rd concerti
Rzewski
Please ignore those comments entirely. Of course, there is an absolutely monstrous amount of music from the many periods which you refer to as "modern/contemporary," so I will stick to just the composers you specifically mentioned.
Stravinsky: there is nothing he wrote that would be within your grasp at the moment that I can also recommend as good music.
Prokofiev: please look at the Visions Fugitives and the Sarcasms, Tales of an Old Grandmother, Two Sonatinas and his Pieces for Children, or you might look at the first two movements of the Sonata No. 4. Please also look at his Opp. 3, 4, 12, 32 and 59 for selected pieces that you might enjoy better.
Bartok: the Mikrokosmos is a huge set of student-level pieces, some of the later ones being fairly advanced. A lot of them sound like exercises, but many of them could actually qualify as real music, as well, and they are usually a bit less exploratory than his major works. You might sift through Books 4/5/6 for a few pieces; I think that would actually be a very good way to acclimate yourself to his music. I am not super-familiar with his small, obscure works (however, he has many), but perhaps look at the 4th movement of his "Out of Doors" Suite.
Scriabin: I would not stray past the Op. 54 mark, to start off with, unless you're comfortable with his late sonatas. Scriabin is perhaps the best composer out of this list to start off with, if you're not really a fan of very "modern-sounding" music, because his music has a lot more direct influence from the Romantics. He wrote swathes and swathes of short pieces prior to Op. 54 in collections of etudes and preludes. Many, perhaps most, of them will be accessible to you, if you can play the Brahms Rhapsodies:
https://en.wikipedia.org/wiki/List_of_compositions_by_Alexander_ScriabinNaxos released his complete piano music, and I'm sure that all of the sheet music is on the IMSLP. Spend a few days or a week going through the Etudes, Preludes and Poemes from that era of his music, and find a handful that you like. I'm sure there will be more than just a few!