Is there a website for Ghana whereby a Ghana citizen can apply on-line? Where does a Ghana citizen go to get the visa and passport for this trip? Any telephone numbers in Ghana that you might have?

You don't make those applications online... for some very obvious reasons. Go to the American Consolate, as well as the Mexican Consolate. As it takes TWO Visas not just one.

They apply for the passport locally and for the visas at the US and Mexican embassies in Ghana.

There is not a specific passport, there is one passport, they will get the visa though the country they are visiting,

A passport will take about 3 weeks, one if they rush it.
Passport and visa would not be over 300 dollars.

The US embassy web site to Ghana, includes a lot of good info, along with warnings of the 10's of thousands of fraud dating done there.

If you meet someone who after a little bit just loves you, or is in danger or needs more than a few 100 dollars it is a scam