There are no two people who experience hypo or mania in exactly the same way.
Lots of similarities, bits and pieces will be the same but people always seem to
have some things that others do not experience.
I am bipolar 2 and I don't believe I have ever experienced full blown mania.
My hypo shows itself as agitation, fearlessness as in crazy driving and lack of
patience where normally I am a pretty patient guy and bad decision making.
Without meds I don't sleep much at all and still seem to function, though I will
not make good decisions at that point and my perception of reality becomes
a bit off or a bit twisted.
Also my doc. changes his mind about my diagnosis between bipolar 1 and 2
though I believe I am surely a 2. with rapid cycling.
Your first question I believe is unique to the individual IMHO. ( I am not a doc.)
Your second question, I do believe it can fluctuate. Maybe some form of rapid cycling
or a mixed state, which I think I experience at times.
Please remember I am not a doctor and I don't claim to know everything about bipolar
I can only speak from my own experience.
Best of luck to you, I hope you get it all figured out.