Alaikumassalam wa rahmatullah,
Soohaana, pronounced [(SOO)n] + [(HA)rd] + [(NU)mber], is an ancient Arabic name without a clear meaning, it comes from the SAD-W-H6 root which has meanings of "dryness". It is not a Quranic name, but since it doesn't have a bad meaning it is acceptable to use it. It also has a male version, Soohaan. It can also be spelled as Suhana, Suhaana, Suhanah, Soohana, Soohanah. It is spelled as صوحانة in Arabic.
From what I can find Suhana is also a Hindi name meaning "beautiful", "lovely". Since it has a good meaning, it is acceptable to use it. This is probably the name you are asking about. It is probably pronounced with a quicker Su sound than the Arabic, as in [(S)ummer + p(U)t].
As for Siddiqah, please see this page: Siddiqah