It is likely that Abraham, like his father Terah, worshipped the patron God of Ur. All the evidence suggests monotheism didn't exist before the Late Bronze Age which coincidentally happens to be the time of Moses. There is also evidence from a variety of sources that Abraham and his clan integrated with the Canaanites. If this indeed was the case, it is likely the God worshipped by Abraham was in fact Moloch. Abraham would become a major historical figure, he and his offspring were probably immortalised in regional folklore as well. However, the only characterisation we have of Abraham comes from Moses some 500 years later.
One thing Moloch and the Canaanites were known for was human sacrifice, in particular child sacrifice. It was done by fire in a contraption similar to that depicted (right).
Sodom and Gomorrah were two asphalt towns on the shores of the Dead Sea. They were two of the five cities of the Vale of Siddim. The geology of the region was very unstable with three tectonic plates coming together on the Jordan River fault. The cities were built directly above all the tectonic activity and all were destroyed with the exception of Zoar (where Lot took refuge with his daughters). The Canaanites were probably a little bit fearful they had angered the God(s). It was just a combination of an earthquake, liquefaction, and a bit of fire and brimstone thrown in for good measure, but people were superstitious back then.
The fire and brimstone destruction of these major cities was a huge setback for Abraham. People were fickle and in crisis, past glories paled. They thought such a major disaster warranted the supreme child sacrifice, the son of their leader. It could also have been due to the treatment of Hagar and Ismael that made the Canaanites believe Abraham had angered Moloch.
When Abraham had no heir from a hitherto barren Sarai, she consented to Abraham trying for an heir with an Egyptian servant girl, Hagar. The union produced Ismael and then lo and behold, Sarai became pregnant. By all accounts Abraham loved his son Ismael but Sarai was now jealous and protective. She insisted Abraham cast out Hagar and Ismael on the flimsiest excuse. Abraham is said to have reluctantly complied. In effect they were cast out into the wilderness and left to die.
This practice may not have caused a stir in Abraham's native Ur but the scandal it caused among the Canaanites would require some remedying. The Canaanites were beginning to lose confidence with Abraham. The chronology is unclear but it makes sense the destruction of Sodom and Gomorrah took place after Abraham cast out Hagar and Ishmael. Just as the Pharaoh had blamed the wrath of God on Abraham's behaviour, so too did the Canaanites. Hagar and Ismael survived and went the only way they could, south. Ismael became an archer and they lived on the Red Sea coast of the Arabian Peninsular (encompassing modern day Mecca).
Whilst human sacrifice, notably of children, may have been quite normal to Sumerians and Canaanites of the period, this was devastating for Abraham. Isaac was his only heir (he assumed Ismael to be dead). I suggest the whole 'God told me to sacrifice him' thing was actually pressure from the people who assumed it was what would appease Moloch. No doubt Abraham was a tad reluctant but went off with Isaac, two slaves, and a big bundle of wood. Perhaps he needed time to think. Quite how Abraham managed to talk his way out of not sacrificing Isaac is anybody's guess. Moses gives an account but having already established his overall account as being 'shaky' it would be foolish to put too much credence into the closing statement.
There is the possibility the house belonged to one of Lot's daughters, two were stated as living within the city with husbands. From an encampment outside the city a huge earthquake and 'fire and brimstone' could be observed in relative safety. Lot's wife may have been struck by an errant lump of volcanic ejaculation, or she may have simply seen the start of the conflagration and went to try and save her daughters. In any event, she perished as did they and Lot was left with just his two younger daughters.
Living in a cave outside Zoar an incestuous relationship developed between Lot and his remaining daughters. The region whose cultures are somewhat misogynistic by nature, quite bizarrely state the daughters drugged and raped Lot. For some inexplicable reason if a man rapes a woman it is because she is a temptress who bewitched the poor man. It is much more likely Lot abused his daughters and from the unions were born Moab and Ammon, progenitors of the Moabites and Ammonites.
Abraham is considered key in monotheist religions but I cannot find any association between them. It's a bit like saying Noah was a Christian. How could that be, when Christianity didn't happen until 3,000 years after Noah. There can be no doubts there is a historical basis for the scriptures but the perception of what happened and what is said to have happened is blurred by time and complicated by divisive opinion.