No, it's not impossible for a female cockatiel to talk, but it is less common compared to males. Male cockatiels are generally more vocal and are known for their ability to mimic sounds and words. Female cockatiels can learn to talk but may not do so as frequently or as clearly as males. Their vocalizations tend to be more limited, focusing on whistles and calls rather than speech.
FEMALE
You cannot. A female cockatiel needs a male cockatiel to mate with her before she will produce fertile eggs. And incidentally, birds do not "fall pregnant".
Yes. Your female cockatiel may lay an egg however without a male it will not be fertilised and therefore a dud.
Yes, they can learn.
A male finch can't really live with a female cockatiel as you should not mix straight-beaked and hooked-beak birds.
Yes, cockatiels love almonds. They have calcium and protein. If you have a female cockatiel feed her these when she is laying eggs.
talk to your vet and see what he says.
Yes, that's how you get more cockatiels.
Maybe. Cockatiels have personalities and chemistry just like humans. My male used to be a jerk to my female, but now they have a baby and constantly preen each other.
The cockatiel can be a very talk'a'tive bird, but it may take you a lot of time to train them. But if you don't give up cockatiels can be taught to say almost anything.
This question makes no sense. A Heath is a small shrub.
I personally have a cockatiel of my own and his playmate flew away. He is doing absolutley fine, I just play with him when I can. I don't think its necessary for you to get a playmate for the birdy. Just train it to be nice. You can be its playmate :D