I don't care for any of these names in particular. Some of them are OK and a few just sound made up to me.
I would say the least masculine sounding to me is Emlyn. There is no way I would ever think that name belonged to a boy.
Jonas would have been pretty good before the onset of the Jonas Brothers Band, now all I can see with the name is somewhat effeminate young men.
I guess the most manly ones on the list, for me at least, are Rowan and Gareth.
I can't think of any "sissy" names that I like. My 2 favorite boy names are Shaw and Sloan. Sloan is almost always on girls now (ggrrr) and while I simply adore Shaw I wouldn't name a child that, simply because I don't see it as a child's name but as a man's name.
I used to think James and Derek were not very "strong" names then I read a few romance novels that completely changed my mind!