The task list will only populate tasks for animals that are currently in custody, so you will want to service animals back in after they have been outcomed if you want to see their scheduled tasks in your task list. 

You can Service Intake animals back into custody using a service intake subtype set not to count towards your numbers so as not to skew your intake/outcome reports (you'll also want to use a corresponding service outcome subtype set not to count towards your numbers when you are ready to outcome the animal). Take a look at this article here for instructions: How can an animal be placed back in our custody after an adoption?

Another option would be to create a pre-intake record then on the day they are coming in for services you can complete the intake from the animal record directly. The date and location you select while doing the pre-intake do not matter since they will be overridden once you complete the intake in the future.

How do I process a pre-intake?
How do I utilize Shelterluv for a vaccine, spay/neuter, or microchip clinic?

In case you haven't already done so, we recommend reading through the article below as it may have some additional suggestions for you with regard to adopting out unaltered animals: 

Best Practices in Shelterluv for adopting unaltered animals