Echostar 15 is CONUS only it will stay at 61.5 (it was previously located at 45w for an ill fated Brazilian DBS venture). Echostar 16 has CONUS and spotbeams. I assume they will locate it at 110W where E18 was first planned to be. At this point, it will provide probably nothing more than redundancy at the 110 orbital slot, where currently there is E11 a CONUS bird and E10 a spotbeam bird. With that at 61.5W they will have E12/R1 for redundancy and E16 at 110W for redundancy.
So, if you are saying that all will be left at 61.5 is E18 then sounds like you are the one that needs to do the research.
I see that you joined here in 2015, the main reason for my post was to highlight the fact that you made it sound (perhaps you didn't mean it that way) that Nelson61 did not have a very good idea of what he was talking about regarding his speculations, when the contrary is true. He has been a a member here since I believe, the beginning, and has made vast contributions to this site with spotbeam maps, etc... For "The List" and from the best I can tell reading his posts, is extremely knowledgeable about satellites in general.