Luella is adorable! I am quite fond of it.
I like Lovell. It's interesting, somewhat quirky, but still formal enough to serve your daughter well later in life.
I don't really like the smoosh name Markay. Is one grandmother Kay, and the other Mary/Maria/Marlene, etc? What do you think of:
Marika [cute Slavic form of Mary]
Marieke [the Dutch form of Marika, 'little Mary']
Mariska [like Mariska Hargitay, the Hungarian form of Marika]
Makeda [the supposed name of the mythical Queen of Sheba]
Malak ["angel" in Arabic]
Malika ['queen' in Arabic]
Mariko ["truth child" in Japanese]
Masako ['proper child' in Japanese; current Princess of Japan]
I think Lovell + any of these sound great, as they have lots of vowels to balance Lovell. Lovell Marika?