No crabs don't know their babies - they release them into the sea while they are still microscopic.
Yes,if you touch there babies in two weeks of birth.
yes, if you touch the baby early or if she is stressed.
if she is eating her babies that means she doesn't think it's her's.the way 2 prevent that is not to touch the babies until their eyes have opened or if they are about 2-3 wks old, because if u do touch them then ur scent is on them now-not her's.
Yes land hermit crabs do lay eggs if you suppose to have a sot of digged up spot in the tank check for a egg but watch out if you touch the egg the mother will not sense that the egg is hers and hermit crabs carry a disease called salmonella so do not touch 
just walk up and pinch it.
Not sure! Checking!
It can be as simple as putting a male with a female for a day or two. dont heat the female just put the male in with the female and they will mate.NOTICE: Once the babies are breed don't touch their bodies or else the mom will eat them.
DONT TOUCH THE BABIES CUZ THE MOM WILL REJECT THEM I HAD A FRIEND WHO HAD BUNNIES AND THE BUNNY HAD BABIES AND SHE TOUCHED ONE BABY AND THE MOM SHOVED HIM OUT OF THE CAGE AND WOULDNT LET HIM EAT AND HE DIIIIIIIIIIIIEEEEEEED true story
You can touch it by lightly pinch it, don't pinch too hard or it might hurt. U can also lick it
They might cause a fight, if same gender, If not the same gender, the they will (most likely) have babies, and when a female hamster has babies, you have to help the babies come out. And if you touch the hamster babies AT ALL, the mother will eat them. I don't recommend buying another hamster.
No because once the female has her baby or babies the male will kill them so the best thing to do is move the male to a different cage and do not touch the mother wile she is pregnant you could harm the babies.
No you cannot you stupid person. no one touches sammy!