Inheritance tax, gift tax, vs income tax

I am the executor of an estate.  we divided the proceeds among my sisters and mom.

 

1.  do we pay income tax?  I see there is not inheritance tax in California. the 2019 response to a similar question said the executor would know but I do not and it mentioned something about a form K-1?

 

2. my mom gifted each of her daughters $15,000.    Do we pay income tax on that gift?

 

Thank you