Budgies aren't allergic to anything, their just not allowed to eat certain foods. Sticky foods may clog their beaks, if this happens take it to the vet right away. To learn what foods their allowed to eat and what their are, you can borrow some budgie books from your local library.
This question is a matter of opinion. Some people like English budgies better than regular budgies or other people like regular budgies better than English budgies.
Rats are not hypoallergenic
well if the cat that the hypoallergenic cat is mixed with isn't hypoall. then the cat isn't hypoallergenic. if the mix includes all hypoall. cats then the cat is hypoallergenic.
Yes, budgies are parakeets.
no
No mice can never be hypoallergenic :)
No. They are from the hound group in which no dogs there are hypoallergenic.
Budgies are parakeets. They eat seed
They actually shed a lot and are not hypoallergenic.
Yes, they're called gay budgies, ey.
Yes, budgies can certainly imitate whistling sounds.
snakes eat budgies so you better watch out