You are right that the Pre-Deluge humans had advanced technology, could build like we cannot today etc.
I don't believe there is any evidence that humans coexisted with dinosaurs, but I am open to evidence along that line. Carl Baugh used to speak of a human footprint in a dinosaur one, but this is not conclusive at all.
I do believe there was a Pre-Genesis 1:2 world with "primitive" proto-humans or hominids. It shows to me God was experimenting in anticipation of creating modern man 6000 years ago.
Hominid fossils are only found in recent strata in the geological record.
re 1:2
The text does not go that 'experimental' direction at all. There are many, many similarities between many, many species human and non-human. That's because there is essentially a good ergonomic and functional design in all cases. Were scientists expecting completely different designs for lungs for each and every mammal?
The 'hominids' look like humans, but so what? Humans are way different. People who believe in millions of years because of the mistaken reasons of uniformitarianism and just looking for various stages they think are there, when the anthro- and geomytho-data is totally different in actuality.
1:2 is about something entirely different. It is about the end of a stage of earth completely unrelated to geology or evolution. The expression 'formless and void' indicates God's judgement on something that was there (like Jer 4:13). Job 38 says God had to shake out the earth like a carpet (to get rid of some kind of evil) before laying its foundations. And 2 Peter 2/Jude refer to the 'blackest darkness' places where evil angels were sent. Well, being limited to just a few clues, guess what condition the earth was when God began creating? Black, dark, deep. The Spirit of God was not at work in it, until creation started, and was withdrawn after evil consumed the earth before the deluge, which is when all magma breaks loose on earth.
We should also note, like Hebrew scholars Waltke (DTS, Regent) and Wakefield, that the defeat of a massive sea-monster by the creator is found all around the world in cosmologies. Gen 1:2 employs this. Something has been destroyed because it was horrible and hostile, and from it the creator makes a beautiful, human-friendly world. The sea-monster is the closest thing to the reality that world legends can get. Compare the ancient Greek 'Hydra' which, of course, is simply 'water.' They are all varying departures from Genesis. But the frequency of it should be kept in mind, and so should the similarities between that kind of geo-hydrological event and the deluge. If Genesis suggests repetition (that the deluge repeats things about creation, see below), why wouldn't other written material? Some do; many simply refer to the end of the deluge as creation, which is perfectly sensible.
Next, we should notice what 'the image of God' means. This is not the physical appearance, and it is not just a 20th century conception of human dignity. A human sovereign would place images of himself around his territory to 'mark' what he owned. Those were usually wood, stone, metal. The text is saying that whatever was going on before, the Lord God was now owner and humans were his 'image' (to whom?) to show that the Lord God was the sovereign of this earth.
So I find that both of these things suggest something horrible and hostile was made into the kind of human-suited world for fellowship between God and man, and that we don't get to find out very much about what was there. The debate between 6 days and 6000 million years pretty much doesn't matter, if you are being honest about the text. Those are not the corners you'd back into. It has much more to do with the supernatural, with legend-clues, with evil angels. There is no reason at all why the Lord God 'needs' millions of years for anything about creation.
Finally, it seems the 'problem' that is behind the very dark (!) Genesis 1:2 repeats. Those evil 'sons of God' show up again (we don't know why), seek out human women for sex, and those offspring make the world a horrible place. We don't know how 'they got loose' but that's life on earth. It is what it is.
But it is extremely different from uniformitarianism. There is no meshing, synchronizing, etc., that comes to mind. On the recent NOVA special "Making North America," the best the writer could do was an asteroid that sprayed a layer of metal particles all over earth X million years ago and dinos perished while underground mammals survived. He didn't say whether evolution was to be reset to start from a 'Noah's ark' of underground mammals, but what other conclusion can a person make? They don't seem concerned to make any sense of that for a national TV special. It's pretty rank nonsense.