LMBO @ your "observations!"
Well, I believe that we are all made up of genetics, experiences, and exposures.
....like the old argument "Nature-vs-Nurture"
But, I think some of that stubborn-ness in me comes from my mother, the Leo! lol Whew! Once that woman made up her mind, JESUS would have to come down and tell her she was wrong! lol
I find that same trait in Aries people too.....And I have 2 siblings who are Aries.....Lawd knows, I bumped heads with them growing up and still do! lol
Well, I just think my soft Pisces self had to learn some "get tough" and "stand firm" cuz people will take advantage of you if they can.
If you are a mid or late Pisces, chances are your mercury is in Aries. LOL, yes, if your mom is the fire sign Leo and you have 2 siblings that are fire Sign Aries, you absorbed just what you needed from them because Pisces are for the most part soft and they will give their last to help anyone, because of that, people take them for granted. So, it's good that you got some of that fire from your mother and siblings but I am sure that you also have some fir signs in your chart, I just know you do.
Your observations of me were right on point.