If the value of the property is restricted by the covenants, then the FMV is determined by those restrictions. In other words, when determining your gain or loss, you would use your basis (the step up at inheritance) and the selling price (plus any improvements, which I am assuming do not exist since it's land). There is no "gift" for selling below the assessed value so long as you have restrictions - that said, if you sell for below value to a friend or neighbor without any restrictions in place, then the difference between the selling price and the FMV would be a gift to your neighbor and could have other tax consequences. Just make sure that you have a tax or legal professional review those covenants to ensure that they are actually enforceable.
If you give it to the homeowners association, there's no loss. You can't take a loss on a donation - which is what you'd be doing. However, if the association has exempt status (not likely but not impossible), you would be eligible for a charitable deduction.