Is this mostly for a small, portable music player? iPod, Walkman, etc.?
Colloquially you can maybe exclude the subject sometimes in English like you're proposing, but it's far from grammatically correct and sounds a bit strange depending where you're from.
I mean, did you really have to write the "it" in "is it really necessary", in your question?...
yes, it is necessary in that sentence. But I hear a lot of people saying : looks like it's gonna rain today or stuff like that. Even in movies. which maybe are not the best way to learn how to speak good english. But what is GOOD english ? my english friend is from Coventry and his wife from London. Their pronunciation is quite different.. Which one is the best ? No idea. An then you have USA english, Canada english Australian, New Zealand, South Africa, Caribbean, India.......... So, I think the BBC english must be the best of all. That's what they told me when I was young and learning your language. Or ain't it so ?
In english we would not say just "player", would be specific, e.g.: "DVD player", "tape recorder", "CD Player," "MP3 player" etc.
Плеер = A cassette or disc player of some kind (if you want to specify it's a CD or DVD player you'd just add CD or DVD in front of it... DVD-плеер).
For Lego you'd want to say something like Фигурка Лего (Lego figure) For Table Football the official word is "фигурка футболиста" (a figure of a football). The word Фигурка itself basically means anything from a figurine to action figure.