The UI in the game is going to to be relatively minimal with an objective labeled on the side of the screen and then the abilities on the bottom corner. This can be done as the objectives won't need to be highland or shown on a mini man as the district will be named and the faulty item you have to repair will be visibly faulty for example electronics will spark and plumbing will be leaky or even smoking electronics.
When you get near items you will have a translucent pop up saying interact with the specific action button for your device you are playing on. Lastly some repairs will have specific UI as they will act as quick time event (QTEs) that will pop up as you interact with he item in on a separate game screen.