Here's my advise:
1. Spay ASAP - 4 lbs is too small to breed, she could die and so could the pups...not worth it IMO - Also, spay with cut her chances of cancer.
2. Her wildness - She should *mellow* out a bit after her spay
3. Honking or snorting when excited. I suggest when you come home, don't make a big fuss, actually ignore her....Come in, go to the bathroom, clean up a little bit, let her calm down and then you can play. This should help with the honking, however, when she does honk, you need to make her stop. A few things you can do is gently rub her throat, talk softly to her, you can try raising her front paws up towards the sky, and even put some water on your finger and get her to lick it (I have heard that stops it too).
4. NO BARK COLLAR ~ Instead teach "Quite" - Get a small treat (cheese, cheerios, chicken) and teach her the command quite. Obviously when she is quite, you say "Quite" and if she remains quite, you tell her good girl and back it up with a reward. Keep doing this over and over until she learns
Best of Luck!