The top knot is the tuft of hair that grows on their heads, some have their top knots cut off and a flatter looking shorter hair on the head.
Some prefer to keep the hair a bit longer on the heads (I prefer it)
You will find that as you go out more walks then the claws will actually start to wear down a bit.
You could get them trimmed though either yourself, groomer , vet or pets at home cut them .
Its probably a little bit early for the teeth to fall out at 13 weeks, possibly in the next couple of weeks.
Riley lost all his teeth between about 16-21 weeks , they were all replaced with big adult teeth in such a short time span.