I'm not a lawyer, but I've done this many times before and I am married to one. Hopefully this information is helpful but you should always consult an attorney and/or an accountant to get the best advice for your situation.
It sounds like the only reason you want to include your spouse is for the scenario where you are incapacitated and unable to run the company. This should be handled by estate planning; see an attorney and set up your estate plan together if you don't already have one. You should have wills, medical proxies (if you want them), powers of attorney, etc. In this case the power of attorney would be the document that would empower your spouse to make decisions on your behalf. It may be necessary to get a power of attorney document that explicitly mentions the LLC, but that's a question for an attorney.
For tax reporting, you're right. You can file a Schedule C for single member LLCs. A K-1 is used to to break out your percentage of tax liability for the company. As a member you're responsible for the taxes of the gains, and can use losses against your taxable income. If you were both 50/50 owners, you'd need to make and distribute K-1s to each of you. Then you'd each enter those numbers in your tax returns. If you're filing jointly anyway, the whole thing is a lot of extra paperwork for no real extra benefit IMO.
The LLC should shield you from any liability as long as you operate in good faith. No reason to bring anyone else in for that reason.
You should get an EIN. It takes 10 seconds to get one, and many Individual 401k plans require one (if you plan on going that route...) If you ever DO get sued and need to use that limited liability, it's better to have your assets in an account that has no reference to your personal SSN on there. It's free, easy, and opens doors to some excellent retirement account options - no reason not to.
Hope this helps.
Eric
