I believe the connection to MLADEN is a mistake. Milada is much more likely to have derived from "milý" or some other related word, which could either mean "dear" or have a connection to love. (And thus be somewhat related to - but not necessarily "a female version of" - MILOSLAV or MILAN.)I don't have any sources at hand at the moment, but it's unlikely that an "I" would have been inserted between the M and L in deriving a female version of Mladen - there is no reason for it. It clearly has not happened in other Slavic languages in their versions. But even more importantly, with its insertion the meaning would change, as demonstrated by my own impression of its meaning above. So they would not have done it that way. [noted -ed]
I don't have any sources at hand at the moment, but it's unlikely that an "I" would have been inserted between the M and L in deriving a female version of Mladen - there is no reason for it. It clearly has not happened in other Slavic languages in their versions. But even more importantly, with its insertion the meaning would change, as demonstrated by my own impression of its meaning above. So they would not have done it that way. [noted -ed]