I don't think Alexandra would have deliberately used her daughters' marriages solely for political gain. She realized how very lucky she was that her own marriage was a love match, and hoped for the same for her children, although Alix was a little fearful of letting them go. (There's a letter from Alix to Nicky that says all this, but I'm not sure when it was written, or whether I can find it.)
For example, the IF went to Romania in 1914 so Olga could meet crown prince Carol, a possible suitor. Olga showed virtually no interest in the prince, and the issue was dropped. (Carol later brought up the idea of marrying Maria, but Nicholas dismissed the proposal, saying Maria was too young.) Olga herself told Gilliard, "I am a Russian, and I intend to remain Russain," and I don't recall reading anywhere that Alix ever pressured her daughter one way or the other where the possibility of marriage was concerned.