I prefer [name_f]Alina[/name_f] over [name_f]Marlena[/name_f], but [name_f]Lena[/name_f] (still pronounced [name_u]Lee[/name_u]-nah) over [name_f]Lina[/name_f]. I have a little cousin named [name_f]Lena[/name_f], and it reminds me of her 
Might I suggest [name_f]Milena[/name_f] (Mih-lee-nah) nn [name_f]Lena[/name_f]?
I like [name_f]Lina[/name_f] better, but feel it creates pronunciation problems.
I prefer [name_f]Lina[/name_f] to [name_f]Lena[/name_f] and [name_f]Alina[/name_f] to [name_f]Marlena[/name_f].
Also, if you end up going with [name_f]Lena[/name_f], expect a lot of people to pronounce it like [name_f]Lina[/name_f]… I thought you were just choosing between two spellings of the same name until I read your pronunciations.