I agree on number 3-4, bitcoin forum of course is the best way, telegram yes also. On twitter I don't know, i do twitter but not that much. If i we're to add more ways to promote I'd put Instagram, facebook and youtube on the list. This 3 of my choices are on the list of the biggest social media so this will really work on promoting ICO's.
Everything is a good medium, we can generate many benefits if we can take advantage of everything. For me every media must have its advantages and disadvantages so we must know how to do the best in every media. Because as good as any media used but when we can not maximize it then it will be the same and will not be meaningless. Anyone who can make the most of it is sure he can do the best.