Are there any comparative studies done between Ashtavakra Gita and Buddhim? I have been in search of a higher truth as far as I remember, like a stargazer looking for the brighter one and dropping the dimmer. I started from Christianity or generally from the Abrahamic religions just because it was close at home, then progressed on to the early Greek philosophy when I found out that the theology of these religions is just a makeshift of Plato's Philosophy.

The Greek thought kept me for a while, especially the Stoics which I still respect the most, but then I discovered the wisdom of the East mainly because of the proximity of the Taoist with the Cynics. I explored the Eastern thought and religions for many years Hinduism, Jainism, Taoism, and Buddhism. I read, inquired and tried to practice some for longer and some for shorter years. There is an apparent similarity between these religions and it can be said that a common theme is repeated again and again 

That said, Ashtavakra Gita is very distinct and truly a higher teaching. I know it is a Hindu scripture, but it’s just by name, the Gita presents almost all Hinduism as a bluff of vanity. By my understanding none of the philosophy or religion of the world that i encountered, except perhaps the higher teaching of Buddhism, Laozi Tao and some few thoughts in the west, will stand its truth.

So, I'm looking for a comparative study between Buddhism and this specific scripture Ashtavakra Gita.
We don't usually compare Buddhism with other non-Buddhist teachings here, both because few of our users seem to know other teachings deeply enough to give them justice, but also because we prefer to stay away from qualitative judgements and arguments, so you're unlikely to get many in-depth answers on this. I can make a few general comments though:

A.G. seems to be mostly in-line with the teaching of Mahayana Buddhism. This is not surprising, considering that Advaita Vedanta is thought (by Buddhists) to be a derivation and adaptation of Mahayana Buddhism for Brahmin audience. 

Unlike A.G., in Buddhism we do not identify ourselves with the mind / the witness / pure consciousness etc. We say that the mind is just an emergent property of nature, whereas "I" is only a concept. Nor do we identify with the All. So the many statements in A.G. of the kind "I am pure consciousness; I am in everything and everything in me" etc. - would sound odd to a Buddhist who would find it misleading.

Then, A.G. seems to describe the target state in considerable detail, but hardly if at all explains the practical path from a typical Samsaric condition to the freedom of realization. In contrast to that, Buddhism declares, and spends a great deal of effort expounding the practical implementation of a gradual step-by-step method for reaching that state, which can be followed by someone starting from complete scratch, all the way to Liberation.

Finally, A.G. does not seem to concern itself with the social morals, while Buddhism defines a comprehensive set of guidelines for regular society which is in complete sync with the Buddhist path and vice versa.

Still, from a quick read of A.G. it seems like it comes from tradition that could be completely at home within the higher yanas of Tibetan Buddhism, especially what's known as Dzogchen. It almost reads like a Dzogchen Tantra and I suspect back when religious traditions were more pliable than they are today, there was likely some cross-pollination between the two.

This similarity is seen in many cases on the Dzogchen side as well, with texts talking about rigpa (ground awareness), making proclamations like "I am the eternal Buddha" and so on. And certainly the spirit of "nothing requires fixing" that A.G. is permeated with, plays the key role in Dzogchen as well.

Since you appreciate A.G. as the higher teaching, I suppose you may enjoy reading about Dzogchen, for example as presented by Chogyal Namkhai Norbu whom I found clear and to the point.