You can obtain Heart Scales from smashing Rocks in Mt.Ember, it's a relatively low drop rate but I got a few from the room in which Entei is located (Just leave and reenter repeatedly), I didn't find any in the cave or the beach route to the south, but they might be obtainable idk.
I have a couple of questions if you'd be kind enough to answer them. First, when using most of the Field Moves, the dialogue option triggers on the corresponding item (Tree, Rock, Water), yet when it comes to Strength, you have to manually select it from the Key Item each time. I know it's only a couple extra key presses if registered but are there any plans to change this so that you can just interact with Boulders?
Also, regarding Competitively Oriented items like Assault Vest, Choice Band/Scarf/Specs etc, is there any way to obtain them outside of the Battle Tower? (I assume since you haven't gotten around to putting Seven Island in, the Tower is inaccessible?)