Question 2: You can make a vending machine activate a new fishing system with a higher probability of getting fish
Question 3: Depends on what upgrades you want. There’s already a guide for the No-Wait one. For the cash multiplier, make a vending machine deactivate the vending machines from question 5 and make it activate new vending machines that the wire repeaters are connected to. Those vending machines are not active on game start and give you more cash per fish than the original ones.
Question 4: Connect a vending machine to a button (item purchased → activate.) Make sure the button is inactive on game start. Connect the button to a teleporter (Button pressed → teleport here.) Place the teleporter at the location you want the player to teleport to. Do the same with the button and teleporter so the player can get back.
Question 5: Sell Station
Question 7: Refer to question 4’s answer