Can I file for the stim packages if I'm a U.S. citizen who's lived abroad whole life, and my parents are non-citizens?

Yes, overseas residents are eligible for the economic impact payment if they meet the requirements and do not have any of the stipulations that make them not eligible.  Your parents do not have to be citizens for you to qualify.

In order to claim the stimulus you must have a valid social security number and not be able to be claimed as the dependent of another person.

Here is the complete list from the IRS Newsroom
 

You are not eligible for a payment if any of the following apply to you:

• You may be claimed as a dependent on another taxpayer’s return (for example, a child or student who may be claimed on a parent’s return or a dependent parent who may be claimed on an adult child’s return).
• You do not have a Social Security number that is valid for employment.
• You are a nonresident alien.
  The following are also not eligible: a deceased individual or an estate or trust.