I've never experienced this, but I love this post! I play with my twin brother and we've noticed a lot of "irregularities" similar to this that make me think it was no coincidence.
My brother and I both hatched a 100% Scyther on the same day! Our eggs were not from the same Poke Stop and we were not in the same location when our eggs hatched (we didn't play together that day). We evolved them and got different move sets.
After celebrating "Memorial Day" in the U.S with my family back in May, my brother and I battled a level 10 Instinct gym while we spun an in range poke stop every time the battle ended. We both had 3 spaces in our bags to collect eggs. He got two 10K eggs and a 5K. I got two 2K eggs and a 5K. I was the first to spin the poke stop before we battled the gym and it gave me a 2K and him a 10K on our first spin. I'm certain if I'd of spun the poke stop 2nd I'd of gotten the 10K. If I told you why I'm certain of this I'd have to elaborate way more in depth and thats a guide I should get paid for.