Well, first do you know how those effects work form an acoustic perspective? If you know how the effect works, then the API for reading the ADC, writing to the DAC, and reading/writing memory should be all you need. Do you understand how the Audio Hacker examples work? For example, the Echo Effect would be similar to reverb, right? Did you read the Echo Effect code?
When you say “realtime control” what do you mean? It’s easy to read values from analog pins. What do you want to do with the values you read?