FM (ultra-shortwave) is a frequency range, while FM (frequency modulation) is a type of modulation. In conventional radio use, the two terms are colloquially used as synonymous. So when the radio is set to FM, it receives the conventional FM stations.
It is a standard "unprotected" 18350 lithium battery with a flat positive terminal. You could, for example, use this Efest battery Purple IMR18350 (flat positive terminal) (1 pc., 18350, 700 mAh, rechargeable battery) but unfortunately it has even less capacity than the original.
Otherwise, just google 18350 unprotected flat and take one with as high a mAh as possible. To be on the safe side, you might want to check the brand of the battery by googling it. Some names have attracted negative attention in the past because of very bad or even dangerous batteries.
Hello,
No, no Bluetooth, it's a radio.
For the dynamo, it's a crank to turn, in plastic that looks solid, to recharge the radio.
Like all crank systems, it's not a "toy" and the aim is to turn for a long time at a constant speed, not fast and hard...