Tweet control of Continuous Servo through GPIO on Raspberry Pi

I'm looking to create an electric dog treat dispenser using a Raspberry Pi 3+.

I'm in the process of writing a formal brief but here is the top level description. Would be good to know what you consider the time / cost should be.

- Simple GUI interface
- Listens for specific hashtag to specific twitter handle
- These two variables should editable in GUI for reconfiguring
- Twitter handles from incoming tweets are buffered in a list to prevent overloading of the food mechanism
- Every 15 seconds the app should look to see if a new twitter handle has been added to the list
- IF there is a new handle then the following things should happen
1) A signal is sent via GPIO to the Servo rotating it 360 degrees
2) A reply tweet is sent on twitter thanking them.
3) The reply tweet contents will be pulled at random from a predefined list of tweets
4) The latest tweet is displayed on a locally hosted web page

(For reference, this locally hosted web page will be accessed using the device's IP address and will be used on Open Broadcast Studio as part of a live stream to Instagram)

IF there is no new tweet the system will try again 15 second later.

The whole thing needs to be functional, but doesn't need to be pretty. Just a very very simple GUI.