This was not fixed for me until I created a new hubitat account using a different e-mail. Just out of curiosity, Are you running multiple copies of the app using the same e-mail login?
See:
Can't answer the other two questions. But, if you hit the gear icon in the upper right, then home page settings, you can toggle on/off the different sections
For the devices section, I don't think you can have it open to that page. BUT, you can add items to favorites so they show on the main opening screen. (They appear to populate in the order you added them)