In the Command GUI you can set commands to execute with Numpad9. Open it with Numpad3. In there you have multiple pages for different commands. After executing, the command of the next page will be used next. Use the check mark to set the start page.
NPCs can interact with blocks. They can use levers, buttons, chests (Only opening animation) and more. Also they can break and place blocks. (Block placing does not work with all blocks!) Just experiment with the possibly actions!
NPC