[Aiwendil]

I would hesitate to move Tuor’s house because, if it were north, it would have been more vulnerable to the initial attack of Gondolin when the hosts of Morgoth came from the North.

I think you're probably right. But I need to think this over a bit more.

FG-TG-11.05
for in great love Idril bore to Tuor a son [and she named him Ardamírë, but his father named him] {and he was called} Eärendil [and by this name he was know ever after].

This looks good to me.

What would such a change imply actually? Only the insertion of the name Sauron or some editing of the sort.

I'm not sure. First of all, we must decide whether to give the entry any consideration at all. Even in ToY, the presence of Sauron is dubious. So certainly when put up against all the previous finished texts that make no mention of him, it is something that could just be disregarded. But 'could' is not 'must'. There may be some desirable way to work it in. If we choose to take the note into consideration, then we have two options:

1. Make Maeglin's capture ambiguous - simply say that he was captured, but not by whom. This has the advantage of not imposing a decision on the canon. It has the disadvantage of leaving out information and probably also of stylistic discrepancy.

2. Explicitly state that Sauron captured Maeglin. This has the opposite advantages and disadvantages from above (though it may also suffer a stylistic disadvantage in comparison to the Lost Tales account).

Option 3 is, of course, simply to disregard the note.

I know what you mean but, that Tale of Year is version C, the later version D, has no indication about this.

True, but I think it's very possible that some material that was left out of D was not actually rejected, just omitted. Also, the exclusion of this annal from D might imply the rejection of Ulmo's last warning but need not imply the rejection of Ulmo's counsel to go to war (which was not explicit even in version C).

Overall, though, I think you are probably right that we should still leave out Ulmo's first suggestion. It may have been retained or it may not, so the safest course would be not to include it.

But what do you think about Ulmo's last warning itself? Might this be inserted into the Tale somehow (as merely a repetition of his advice to abandon Gondolin)?