I just responded to a similar question about the same initial. I think if the balance of sounds is good, the names together with a repeating sound can be emphatic rather than sing-songy. It really depends on the names you are pairing. If they actually rhyme, I think it’s pretty bad. I don’t know - [name]Dwayne[/name] [name]Wayne[/name] worked it (on “A Different World”!)
A name like [name]Kate[/name] Spade almost rhymes but stops short, because the T and the D, while as close as can be, are not actually the same. [name]Kate[/name] Spate is really different and distinctly yuckier. [name]Helen[/name] Keller is another example - The Hele-Kelle is so close but turns out ok with [name]Helen[/name] ending with an N and Keller with an R.
Others that you list have a lot more going on that they don’t have such obvious issues. I think in careful doses, this can make a really distinct and memorable name, but if it actually rhymes, it will sound like a character in a story. If the name is one syllable (or the more obvious nicknames are), and that whole sound is actually rhymed in the last name, I think it is chancy. [name]Michael[/name] van Dyke sounds ok until it’s shortened to [name]Mike[/name] (not inevitable but too highly probable). Same for [name]William[/name] ([name]Will[/name] or [name]Bill[/name]) [name]Silver[/name], or [name]Martin[/name] ([name]Marty[/name]) [name]Hardy[/name] or [name]Susan[/name] ([name]Sue[/name]) [name]Lewis[/name]. [name]Anne[/name] or [name]Anna[/name] [name]Flanagan[/name] is somewhat cute, so there are exceptions that are borderline. Try them out beforehand. A longer last name with some other interesting syllables could offset this and make it sound ok again. Others may like a variety of sounds to clarify the names, but repeating sounds can be worked with and even interesting and do make for a memorable name, which can be an asset.