بسم الله الرحمن الرحيم
(1) Tasneem is the name of a river in Jannah. We could not get the meaning of Myesha, so instead keep the name Ayesha or Maria etc.
(2) You can make Fatimah the second part of name, except in cases when there is any issue in making it second part of name according to Shariah. However, there is no harm in keeping the name as Shabnam Fatima, Aisha Fatima, Maria Fatimah etc.
Allah knows Best!
Darul Uloom Deoband