She can apply for her parents, and her siblings, but separately - her siblings (including the 16 year old) cannot come on her parents petition.
Her parents can petition them once they are in the US as you say. The 3-5 years would be for any that qualify under F2A, any that don't will come under F2B and they will have a 15 year ish wait, if they are from the Philippines. The current visa bulletin is here so you can see what date those who are now becoming eligible for visas applied - https://travel.state.gov/content/travel/en/legal/visa-law0/visa-bulletin/2025/visa-bulletin-for-august-2025.html
Also, this is assuming none of them are married?