I have seen some projects doing an ICO first, before going for an exchange for an IEO, one example is DEXAGE and this could become a practice, I don't like this idea, it's pushing the project funding timeline to its full limit, they should just choose between the two, if the project is good it will be funded, ICO or IEO.
they move not only based on team thinking. I am sure some investors will certainly provide input by means of their sales. IEO or ICO is not a problem, but IEO however is now the best way to see good projects.