You'd have to assume that Adult Princess Zelda returned the OoT to the past in the same way she did Link. You'd also have to assume that the seven or six sages were later woken in Child Hyrule to reinforce the seal on Ganondorf. Remember their on the stained glass windows in Hyrule Castle in TWW.
Actually, the Ocarina isn't a problem. Well, it is a problem, but it's a problem in both timeline theories I presented. I didn't count that as an assumption because every theory had to make that assumption. Even if adult OoT happens 7 years later, we still don't have definite evidence of where the Ocarina is.
I understand your point with the stain glass windows. As of right now, we don't know anything about TP, so I'm not going to say, "Hey, wait until that comes out, and then we'll talk about this." I will be upfront. Is there a problem if adult OoT is erased? Yes. The theory is not perfect.
I have a question. Is is ever said in TWW exactly
how the people of Hyrule found out that Rauru and company were Sages? As far as we know, Link could have told them. When you have the Triforce of Courage inside of you and the mark to prove it, people are very likely to believe you. That's an assumption, though.
I'm going to try to say this in the best way without confusing myself and others. The two theories I gave above were about OoT, not TWW. I'm not saying that I'm completely disregarding the point you made; I actually plan on addressing that. The reason I said that is because if we are going to deal with all assumptions tying OoT/MM/TWW/ALttP/etc. together, we'll have to do it for both sides of the arguement. Basically, what I'm trying to say is that even though the stained glass windows are a problem, they are not a problem when the debate is soley focused on adult OoT. To make things clear, I count what you said as an assumption, but only when we are looking at a debate about the bigger picture, not just adult OoT.
Anyway, this is where we are getting into what people see as acceptable when dealing with a timeline theory. For example, let's take a look at all of the assumptions required involving my beliefs regarding and connecting OoT/MM/TWW/IW/ALttP. To make my beliefs clear, I think that OoT is the Imprisoning War, TWW is a "what if", and adult OoT is erased. Let's take a look at all of the assumptions that would make that work.
1. Does some event happen differently after OoT that would lead to TWW instead of ALttP (like Ganondorf escapes the Sacred Realm in one reality, but he remains inside in another.
2. Did the IW legend change overtime from the story of OoT?
3. Is Ganondorf sealed in the past at the moment Link arrives after Zelda sent him back?
4. Does some event happen that would allow the erased events of adult OoT to be remembered (note: This would allow people to tell the story of the IW legend, as well as know that Rauru and friends were the Sages)? These events could include the Sages retaining their memory, Link telling everyone about adult OoT, or etc.I think the Giant is still saved because there are multiple Links running around. When Link goes back in time, the Link who was already there will still be there. They all go about their quests until everything is completed. In this timeline, some Terminas are destroyed, but an infinite amount are saved.
That still doesn't explain how the Giant can be free many hours before Link even freed him in the previous cycle. Plus, here's proof there are not multiple Links. Let's say that you beat Odlaw and his dungeon already in a previous cycle, but you want to return the swamp back to normal in the present cycle. Let's say that as soon as you are returned to Day 1, 6:00 A.M., you warp to the swamp, beat Odlaw by
Day 1, 12:00 P.M. The swamp will return to normal. After you do that, play the Song of Time and go back again. In this cycle, if you do not return to the swamp and beat Odlaw again by Day 1, 12:00 P.M., does the swamp still return to normal? No, it does not. There's proof there aren't multiple Links running around during MM. There is only one Link at a time in MM, unless you are 73h 1337 h@x0r2, and I, personally, don't think that 73h 1337 h@x are canon.

Or: Does the timeline split?
Oh, true. I didn't worry about including that because the assumptions for that would basically be the same as if it's erased, except we'd add the assumption that the timeline splits off, so it would have 2 assumptions.