Baby Names and the Hive Mind
There are probably a number of factors at play here. 

One important contribution to the "snowballing" of trends like this is the mere exposure effect by which things we encounter repeatedly become more attractive to us just because of their familiarity (this is also the logic that underlies ad campaigns that just put the brand or logo all over the place without bothering to associate any particular messaging with it --- just hoping to increase the number of times people see it). Notice how similar the list of names you have are to each other. Repeated sounds (the "ia" ending, the use of nasals and liquids like "l" and "m" in place of harsher stop consonants like "t" or "p"). 

You (and everyone else) has been encountering names with these components, and these names in particular, increasingly over the last couple years, which make them seem more and more attractive to you.