If my gerbil got out of its cage and hid, I would look in:
This is perfectly normal. They are trying to hide the gerbil from you and to keep them warm. Maybe leaving them alone would help.
That means that the gerbil is at the right age and wants to mate.
Yes they will
Most gerbils will LOVE seeds as they contain a lot of fat, which is why it is best to offer them as a treat, as putting them in their food can cause them to selective feed and become overweight. Your gerbil probably sees the seeds you give them as some kind of "treasure" and so will hide them so no other gerbil can get to them.
Gerbil. They are not nocturnal, they smell better, and have tails. (I would recommend getting two)
Yes, it is possible and likely that the cat would try to catch, kill and maybe eat the gerbil. You should keep the gerbil in a cage that isn't accessible by the cat.
Furred
Yes
YES! it would be creepy not to; just having a dead gerbil sitting there. YUK!
It would be best not to get the gerbil wet. They are desert animals and need very little water, so it may drown
No. They are two completely different species. Chances are the rat would attack the gerbil and possibly kill it.
probably because your gerbil loves peanuts more than chocolate drops and doesnt want the other gerbil to steal its peanuts