Well I finally began shiny hunting in Moon version, which marks my first time shiny hunting in Gen 7 hee hee. I'm kind of nervous cuz I'm using the S.O.S. method to find a shiny Mareanie, which seems hard and I don't even have the Shiny Charm item to help me out. Any ways, I'm also multitasking and doing more soft resets for my ongoing shiny Giratina hunt as well, which I've done about 5,000 soft resets on by now. ^^;
I'm pretty sure you can't SOS chain a Mareanie because to get it to spawn, you have to chain Corsola. When you have a SOS chain and a different species appears, it will not chain.