I think hotdogs would be bad due to salt intake, this is what i've found about hotdogs Common hot dog ingredients include
  • Meat trimmings and fat
  • Flavorings, such as salt, garlic, and paprika
  • Preservatives (cure) - typically sodium erythorbate and sodium nitrite
Pork and beef are the traditional meats used in hot dogs. Less expensive hot dogs are often made from chicken or turkey. Hot dogs often have high sodium, fat and nitrite content, ingredients linked to health problems. Changes in meat technology and dietary preferences have led manufacturers to use turkey, chicken, vegetarian meat substitutes, and to lower the salt content.

I use hotdogs as training treats, i nuke them just before they get burnt and cut them into small pieces. So they only get no where's close to even quarter of a hotdog.
As for avocado's i think it would be the high fat content but i know the high fat content is actually the "good" fat. I would think they shouldn't eat the leaves and pit.