1- I have not found any references of how long they live. Or, for that matter, how long any of the races live. For the time being, I'd just apply human years to everyone while avoiding specific age topics when talking with other people. You know, just in case.
2- Technically anywhere. I think I've seen Miqo'te NPCs almost everywhere, so you can very easily say your character was born and raised in any of the city-states. I think there's also a specific location you can visit in-game that is a Seekers' village, but I haven't personally reached that place.
3-Check this Miqo'te Naming Conventions thread in the official lore forums. That should give you an idea of how tribal/traditional Miqo'te culture works.
Hope this helped a little bit, at least!
2- Technically anywhere. I think I've seen Miqo'te NPCs almost everywhere, so you can very easily say your character was born and raised in any of the city-states. I think there's also a specific location you can visit in-game that is a Seekers' village, but I haven't personally reached that place.
3-Check this Miqo'te Naming Conventions thread in the official lore forums. That should give you an idea of how tribal/traditional Miqo'te culture works.
Hope this helped a little bit, at least!