In this theory i won’t tell you who exactly Luffy’s mother is, but i’ll try to bring out her personality.
Vinsmoke Family
So, Vinsmoke Judge wants to create a strong army using his own children and Judge had removed all of his children emotions before they were born.
But unfortunately, Sanji have emotions like his mother and expresses what he want not like Reiju (she didn’t want her brothers bullying her like they did to Sanji)
Sanji’s mother. Sanji’s personality is almost the same with his mother.. Sola was a very kind and caring woman, with great strength of character. She loved her children and was fiercely protective of them, believing that they should grow up with normal human emotions and not as cold killing machines. As a result, she did everything in her power to resist her husband’s experiments on their sons, to the point of sacrificing her own life. So Sanji inherited his personality from Sola.
Sanji’s Father. I’m not really sure in which way Sanji inherited his personality from him. I think Sanji inherited his body endurance from Judge.. but it’s so complicate to see their equation since Sanji’s power and dream are from his truly father (Zeff) 
Reijuu. She inherited her personality a bit from her mother but she can’t express it because she’s afraid with her brothers and father.
Ichiji, Nichiji, Yonji. They didn’t inherit anything from their parents’ personality even from Judge because you can see that Judge even cries when the wedding is becoming an disaster.. that’s because Judge removed their emotions..
SUMMARY
Sanji and Reiju personality inherited from their mother.
No one inherited personality from Judge
Sanji gets his ability and dream from Zeff
Monkey D. Dragon
Dragon looks like a truly a Leader from what we’ve seen. Revolutionary Army is doing his job carefully.. so Dragon looks clever.
His aura looks like Gol D. Roger
Monkey D. Garp
He’s supportive person
Loves his family
He’s loyal with marine (but family first)
Different with Dragon, Luffy looks stupid xD but sometimes he’s cool and clever too especially in fights..He lives freely, he always do something reckless that could make big big trouble~ so i think he’s “Act first think later” Guy.
He’s creative (he makes fight skill spontaneously like gear 2 and 3) and he’s stubborn.
LUFFY’S MOTHER
(Just a pic, not included with the theory)
Luffy is almost the same like Garp and Dragon but still.. he have different personality with them and could be that inherited from his mother like:
– always do something reckless
– stupid but funny
– creative
– stubborn
but in their family I believe Luffy’s mother have this personality too:
– Live freely (do what she;s wanted to do)
– caring her family or nakama
– not lives in regret
That’s all!
*Theory by Denref