If you state their origin by the locality the Five Works are Indian in origin, it is misleading to divert the discussion to all the chinese buddhists that there are! The chinese buddhists generally accept the existence of Maitreya and Tushita devaloka, I don't think they would have much difficulty in this. The pureland school of China talks of Tushita devaloka, it is an existing realm for them. The argument is based on reality, reality which most scholars seem to be unaware of, unfortunately.
I don't understanding your arguments, for a good analogy, I'm talking about apples and yet you are jumping over to oranges.......If you don't bother to read and understand my arguments, please don't try arguing. Its rather embarrassing........really........
No one deny the existence of Matireya not even the scholars, although I know of people here who supports the idea of a human teacher called Maitreya behind those five works rather than the Bodhisattva, Himself. Scholars do know more about the historicity of sutras, sastras, etc, and much more qualified than you do. Before you disregard them as some misinformed dudes like you did in another thread, please take a good look at your credentials first, please.
From the Five Works of Maitreya also Ratngotravibhaga has been translated into chinese, see the wikipedia article about it It has been highly influential in the far east too.
Five works of Matireya in Chinese Buddhism are as the following:
1) Yogacarabhumi sastra (only a small [part is translated into English)
2) Yogavibhaga (Reputed to be lost)
As you could see, its very different from the Tibetan's five works of Maitreya. Abhisamaya-alaṅkāra and Uttara Tantra Shastra are not within the list
. Xuanzang, a reputed Yogacara scholar and fanatic, never mentioned about Abhisamaya-alaṅkāra at all even though he travelled all over India and central Asia in search of Yogacara teachings and teachers. In fact, according to the Chinese, Uttara Tantra Shastra are said to be authored by Sāramati, not Asanga or Maitreya.
Hence, both works are not considered in the five works.
Btw, regarding the last point that I made, your above link reveals the information as well. Why don't you read your own link first before telling others to do so............sighz........