Merely being listed as a co-owner does not, in itself, give you any cost or basis in the land since you had said the economic risks and benefits are "in the owners name"
From the limited facts presented the land is a capital asset. Whether you will have a gain or loss depends on the value of the land you will get as compared to the principal remaining on the loan.
Since you are a shareholder there will also be a capital gain or loss on your disposition of your stock in that corporation. Again, this may be a gain or loss depending on your cost basis of the stock compared to whatever consideration you get for the stock.
From your description it seems that there is one planned sale, or exchange, involving all of the items you mentioned. Of course, this should all be documented in a sales agreement with legal advice. It could be structured as two transactions but the net effect for tax purposes will be the same if both occur in the same tax year.
Basically, I am saying that these are capital assets (from your description) and you can estimate your gain or loss by comparing your total cost of these items to the value you will get for the assets.
For a more accurate computation of the gain or loss it is advisable for you to engage a tax practitioner that you can consult with all of the detailed facts and amounts for the land, loan, small fare and S corporation stock.
Based on that analysis it may be possible or beneficial to use two transactions in separate years or to leave it as one sale, or exchange, within one tax year.
Hope that clarifies for you even though you should get a more detailed analysis based on all the facts and circumstances involved. Let me know if you need further clarification, please.