Retirement tax questions

Thanks dmertz and was very helpful.

I read the other Turbo tax reply said : Sep contribution should be box 12 on W-2? I confused.

 

I am 100% owner S-Corp and employee shareholder and my wife is an employee, should I contribute for her as well is it necessary?

How about 401K and solo 401K for me and my wife? what happens on W-2 boxes?

How much can S-Corp contribute to my 401-K and how much can I contribute to my 401-K as an employee? and my wife?

And above question for Solo 401-K as well?

How about Simple IRA ELECTIVE OR NON-ELECTIVE I dont know about the differences?

Is HSA included box1 W-2 ? I mean should pay FICA for HSA? and State wages included HSA?

Please clarify for State wage for all above SEP, 401-k, solo 401-k, Simple and HSA.