In principle I agree that there is nothing wrong with "es extraño para ella hacer eso", but perhaps it's the slight nuance in the sentences point of view what doesn't match...
Es extraño que ella haga eso. -> The speaker feels she's having a strange behaviour.
Es extraño para ella hacer eso. -> She feels strange doing that.
No es extraño para Juan competir en carreras. -> Juan usually competes in races and is used to them.
No es extraño que Juan participe en carreras. -> The speaker knows that Juan usually competes in races.
Es muy extraño para mí hacer dos goles... -> I'm not used to making two goals (either I usually make more or I make less.)
Es muy extraño que yo haya hecho dos goles... -> Something beyond my control made me make two goals.
I'm not happy with "¿No crees que es extraño para ti hacer estas cosas?", since I'd prefer "¿No crees que es extraño que hagas estas cosas?". Still, one may say "para tu comportamiento usual, es extraño que hagas estas cosas", where "para" compares what someone's usual behaviour is and what is strange in the things he/she is doing now.