Your page implies that Black Tower/White Treeguts must be beaten in its entirety to unlock the market, but I have two salespeople already in my Black City's market. I -think- it unlocks after clearing Area 5 (it's definitely not available from the start), but I'm not sure, I might've unlocked it sooner without noticing. Something you should look into.
After you help Cheren investigate Pinwheel Forest and talk to Rood, he gives you another Up-Grade. Technically, this is earlier than the Striaton City Up-Grade, but it should be listed in any case.
The Toxic Orb and Flame Orb are both found in Reversal Mountain, but they are version-exclusive. The Toxic Orb is exclusive to Black 2, whereas the Flame Orb is exclusive to White 2.