In LPD's RP system (Longman Pronunciation Dictionary) here are the pronunciation of those names.
Daniel, Daniell /'dæn jəl/ (BrE and AmE)
Danielle /ˌdæn i 'el/ (Main BrE and AmE) or /dæn 'jel/ (alternative BrE and AmE)
/i/ is pronounced either as i of /fit/ or as "ee" of "feet" but as short as possible.
According to what I could hear, nowadays /æ/ in "...