Small EVAP leak

Replacing random parts is by far the most expensive and least effective way to solve this. Most often we inject the smoke at a test port or at some point under the hood. This system includes the gas tank, charcoal canister, and the hoses between them. They might not be waiting long enough for the smoke to reach the leak, or the smoke could be condensing in the hoses before it reaches the leak. Have them try injecting the smoke at various places closer to the gas tank. Spending more time that way will cost a lot less than throwing random parts at the problem.

Given the age of your vehicle, dry-rotted hoses and rusted hose clamps should be the last on the list of suspects. I'd more likely expect to find a leaking valve or some other mechanical failure.