Re: Zangoose training?
Egg moves can only be passed down from males. So you'd need a male Seviper with Night Slash. Which means you'd need to breed it with a female Zangoose (not Zulu).
So to get the egg move Night Slash AND pass down the Speed IV you would have to do the following:
-Breed Zulu (holding Power Anklet) with Female Zangoose
-Result: Female Zangoose with 29 Speed IV
-Breed Female Zangoose (holding Power Anklet) with Male Seviper with Night Slash
-Result: Zangoose with 29 Speed IV and Night Slash.
-Keep breeding Zangoose until one of them has the correct nature*
*Only females can pass on natures, so you can't pass on Zulu's nature by giving him an Everstone. You'd just have to keep hatching Zangoose until you get the right nature.
It's a bit complicated so let me know if you need any more help =)