I honestly don't think your mom would be angry if you wanted to name your son after your dad. She knows you love him and you obviously still have a good relationship with him if you want to honor him. Plus, like you said, there is more than one family member you are honoring. I say if you really love the name, go for it!
Completely this, especially as you are not using the name solely to honour your father, but also your husband's side of the family. Good luck!