3. i've just been doing block chords so far and that has been challenging enough. How do I play these charts in a more realistic groove (you mentioned bossa nova and I have no idea what that is)
just play something in time, so you can feel the time. sometimes there's 1 chord in a bar, sometimes there are 2. if you are just playing the chords with no time, then the song won't make sense at all. use whatever groove is the simplest and most comfortable for you, but also doesn't bore you