Shu Nu is described as a Gate of Dreams or a Fortress of Dreams
Seems to me that it refers to 守夢. The first character 守 means "to protect/guard/defend", and the second one 夢 is "dream". However, the reading of this word is "shu
mu", not "shu
nu". I would use 夢関 "mukan/yumezeki" for Gate of Dreams/Fortress of Dreams, though.
Shora is a woman by title Red Lotus.
I'm not proficient in kanji but I thought 蓮 is the only one kanji for lotus and is read as 'ren'.
I can't make connection if these names are somehow connected to their description or they stand for some other meaning. Or they have some old readings or Chinese influence.
Yes, lotus is 蓮, reading "ren" or "hasu". Red lotus is usually written as 紅蓮, reading "guren". 朱蓮 also can mean red lotus, but the reading is "shuren".
The Chinese pronunciations of 守, 夢, 蓮, 紅 and 朱 are shou, meng, lian, gong and shu, respectively, so those are not Chinese readings, either.
Anyway, those words are the author's coined words, and they don't sound like Japanese words to my native Japanese ears.