I can see from your post that clearly care a whole ton about IVs, and that's cool, but I think you should just let them be happy with their Deino, regardless of its IVs. Anything that hatches from eggs has okay IVs, and not everything needs to be 100% IVs. IVs only have actual meaning if you plan on powering your Pokémon all the way, and even then, the difference between an 80% and a 100% is marginal at best.
Personally, I'd take a 0% Deino right now. I just want a Hydreigon, and I don't care what its IVs are.
Tis true. I mean I can't scoff at that whole thing given my 100% Mewtwo, Latios, & Lugia; but a good portion of my Pokemon Go friends usually have 100% IV Mons right as they release - so I can't help but be a tad biased towards CP. If it isn't that, then it's completing a living Pokedex.
As for this Community Day... Uh... I'm going to have to go with consensus, Niantic really should've went along with the Unova starters and everything already. There's no shortage of Mons to use to highlight as Community Day Pokemon if they want to delay the Unova mons due to being "Too New" but whatever...
So results... Since my last post Hoenn Research came and went - Barely got jack in terms of good mons outside a Shiny Groudon, so there's that. Caught a shiny Poochyena the day Sinnoh Research dropped and now I have a 2nd one, evolved that for the Living Dex.
Everyone here had issues with Sinnoh Research and having a Ghost type meanwhile I did a stupid thing and had the Mysterious Box be used to catch Meltan for the Steel-Type Pokemon Requirement - forgot that you can't mass transfer Mythicals. Also got Cresselia for the first time, didn't mind if it was shiny or not, so Living Dex has a new member.
Today though I caught 22 Shiny Seedot, surpassing Treecko & Abra as my most common Shiny Pokemon in Go (Both at a max of 10 - 5 Abra/Kadabra/Alakazam transferred to Let's Go) when I only intended to catch 5 - One Seedot and two Nuzleaf/Shiftry for Living Dex due to Gender Differences. (Really going to help when Go gets compatible with HOME.) I got my first Shiny Shiftry and Nuzleaf as girls, and then got a boy which became my Shiny Male Shiftry, only to catch five females before I got my 2nd Shiny Male to be my Shiny Male Nuzleaf. After that I kinda just said "Meh, I'll continue with this event" and caught/kept any and all Shinies as I could get, while transferring the rest. Got a ton of Stardust as I live in an area where it's mostly Sunny weather and got the weather boost there.
Also got a 100 Shiftry at the end of the Special Research, so that's nice.