Former Skyline employee here- the 4 in 4-way is the number of ingredients. There are 4-way beans and 4-way onions. A 5-way is both beans and onions.
Realistically, the progression goes like this-
2-way- Spaghetti and either chili or cheese, the former they just refer to as chili spaghetti
3-way- Spaghetti, chili and cheese
4-way- Spaghetti, chili, cheese and either beans or onions
5-way- Spaghetti, chili, cheese, and both beans and onions
For coneys-
- Single wiener bun- just hot dog and bun, can also have cheese
- Weiner bun- bun, 2 hot dogs, can also have cheese
- Coney- Bun, hot dog, mustard, chili, onions (if you just say coney, servers will ask if you want cheese because they are 2 separate things, most customers don't know or forget that, its even listed on the menu that way)
- Cheese coney- Bun, hot dog, mustard, chili, onions, cheese
- Chili sandwich- Bun, mustard, chili, onions (same rule with coneys involving cheese)
- Chili Cheese Sandwich- Bun, mustard, chili, onions, cheese
- Coney bowl- bowl with 3 hot dogs, mustard, chili, onions, cheese
Seriously though, if you want good Skyline around the park, the one by The Beach is better in every way (better quality and cheaper) and offers Skyline's full menu (wraps, chilitos, deluxes, burritos, extreme cheese, etc) , and is also one of the better run Skylines in the area to boot.