Not for the motors, and the Grin ESCs are not the only ones available. In any cases, Chinese Kunteng ESCs are also very well made, with an open-source firmware available and provide pure-sine wave control as well as regenerative braking for less than a third of the price of a Grin ESC, and also have headroom (people have been overvolting them by significant margins without issues).
Yes, and they are pretty bad. For the price of a Grin motor you can buy a much better, fully custom QS Motor with components and windings of your own choice, and have enough money left to buy a second one. The Grin motor will be slightly lighter but will also overheat earlier, so there's really no advantage - you can just get a smaller motor and push it harder. Nothing is free - Grin motors aren't really better than anything out of China and for the outrageous price they sell at you can literally get a motor custom made.
