I like the sound of Thalia Blythe, but I'd prefer it spelled Talia Blythe. I think enforcing "TAHL-yah" for Thalia would be very frustrating. I always thought Thalia was a three-syllable name, like tah-LYE-ah or tha-LEE-ah...something like that. Also, I think TH pronounced like a T is a hard sell for many English speakers, excepting extremely common names like Theresa and Thomas.
Talia is so pretty, and it has a pretty meaning, too. I believe it's "dew from heaven."
A few of my favorite names that give me that "strong but sweet" vibe are Rose, Abigail, Eva, Cora, Bridget, Meg (as a nn), Kathleen, Silvie, Shiri, and Bonnie.