-The president to come here is very unlikely.
This is not correct. It should be: "The president coming here is very unlikely." We are using the gerund and not the infinitive because the event has not happened.
-It's very unlikely the president to come here.
This is almost correct. It should be: "It's very unlikely for the president to come here." We need a "for" before the unlikely event we're referring to.
-My suspecs were completely deceiving.
I think you mean "suspects"? If that's the case, other than the spelling error, this sentence is grammatically correct.