Abadom

Probably a year and a little bid

Yeah

Great Ones aren't Gods, they're higher dimensional beings that see the Dimension we live in differently, they could be seen as Gods but its more like they're living beings that exist in a different aspect of reality. I'd say Great Ones are Gods in a similar way Humans are Gods to bacteria

Supposedly he did

I'd say it depends on perspective. The Great ones weren't actively trying to breach your mind, they just try to speak with you. It's a different kind of madness, I'd say its more like being overdriven with knowledge

Its Maria's Gun Skill, she was pretty good with guns so its her shooting skill

She could become a character, I'll have to think a little about it though

They should arrive around the same time Bell left since the only reason he left was because his grandfather "died". In truth, what likely happened is that Zeus opted to leave after he saw that Bell had grown old enough and was capable of beginning his adventure. This may happen earlier though given he has received some training. Zeus' reasons and methods were never revealed so for all I care he may have just faked his death to leave since he was running away from a very angry Hera

The expectation within probable worldbuilding is that some of the Level 1's that joined the familia during this year will be at the high ends of Level 3 or reach Level 4 by the time cannon starts, allowing some of them to maybe reach even higher and be somewhat useful to the story since by now, anyone that isn't a Level 5 is useless to the story of danmachi

That is why he said a lifetime to some, not himself. He can definitely read faster if he masters using Mental Power properly