if has max pop 100 or 102 then its around 890 (if gets triplets at 99 and converts all heathens left before any of villager dies can get to 105-109 pop so around 930 is max at then and if gets good Island Event can get to 112 pop which would raise max energy around 945-950). Bar's max is 1000 but that's most likely only achieved with full relics collection and science collection and 100 pop.

upon completing both science and relic collections my base population is 105 and my energy is now at 925. I don't know if it will get higher but there seems to be more room left in the energy bar.

It is possible for you to get 107 population if triplets are born when population drops to 104. That would mean a further 6 energy points, making the maximum 931.

I have got 975!

I reached 975 in my last game. I suspect the max is 1000 since there was still a little room to grow on the energy line. I finished the game with 115 villagers.