Can I legally receive a "marketing fee" for sending real estate agents customers if I am not a licensed realtor?

Talk to an attorney, but it's likely that paying for leads is okay. Contariwise, sharing in commissions would not be.

This is an "urban" myth. There are no such restricted days.

I am 1/2 owner in a pending $30,000 land sale in Canada. Should I hire my own lawyer, or is it ok to hire the buyers lawyer?

You will be better protected if you use an independent lawyer of your own.

Is a 501 (c) 3 N-PO automatically also Inc.?

Typically, you would form the entity first and only then apply for tax exempt status.

One would have to review the exact terms of the easement to answer this question, but typically an easement would not trump a zoning ordinance.

If a title company insures a title at the sale of the house, how long will that insurance last?

Title insurance is effective for as long as you own the property under the insured deed.

Can she sell the note.

You would need to review the terms of the note and other documents, but it is likely that she can sell the note.

I want to know if my start up nanotechnology company should be an LLC, S-Corp, C-Corp?

It is likely that you will want to have different classes of ownership. That is, some owners will have greater voting rights, some owners will have...

Do I have to give my landlord new keys after changing locks on my commercial office lease.?

At least lock your clients' confidential files and information in filing cabinets. Consider going paperless and keep the records in digitized form.

Am I breaking any employment laws?

I don't see any issue if you want to pay an employee for not working.