[Galin]

My understanding is this. Originally there were to be two separate Eldarin stems, one meaning "reddish-brown" and the other meaning "spray/spindrift".

Yes, two are involved.

The change proposed in "Ros" is that there is only one stem, meaning "spray", and that this is Beorian. But this had to be dropped because of "Cair Andros".

I think that the proposed change was to lift ros 'spray, spindrift' from an Eldarin context -- leaving the other word in an Eldarin context however. Tolkien wrote that it was difficult to accept these two homophonic elements, and so I think he wanted to alter one while leaving the other. In other words, if one is lifted, Tolkien's proposed difficulty of accepting the two homophonic elements is solved.

So as I see it the change of "Maedhros" to "Maedron" does depend on the change in "The Problem of Ros". If we decide to use "Maedron" we are essentially electing to keep half of the change. But my impression is that the whole idea was rejected. Nonetheless it's an interesting question and I'm eager to hear what others have to say.

I think this change is unconnected rather -- at least specifically with respect to the failure of the essay I mean. We are given no detailed context concerning the intended change Maedros to Maedron (despite its implications) and it may be that CJRT found this a convenient place to note the change -- especially considering the first part of note 2 to The Problem of ROS, as we know that the first sentence was added by JRRT to the essay proper:

[added in the Margin: 'Though Maedros is now so long established that it would be difficult to alter'. In a later note, however, my father declared that he would change Maedros to Maedron.]

Even if this later note was attached specifically to this essay in some way, for example, the use of 'later' implies to my mind that this change was originally not connected to the specific thrust of the (failed) solution.

And if it was, I can't think why Tolkien would need to deal with both of the 'two' to solve his problem. It looks to me as if the proposed solution rather centered on a Beorian ros 'foam, white crest of waves', which could further connect to the Ship-name Rothinzil. But Andros had already been published