My wife was told to do the taqlid of Syed Sistani being told he is easy, but never really researched his rulings or never really follows him but after marriage I told her to do taqlid and I her husband am in the taqlid of Syed Khamenai, can she change her taqlid to syed khamenai given she never really followed syed Sistani in the first place

Taqleed is based on following the most knowledgeable mujtahid, not for being easy.
It is not necessary that both couple follow the same mujtahid.