Haileo checked a few of those Mew, here's his findings:
Legit:
- 22796 JP Timid GameBoy Virtual Console GameFreak Mew - Looks good.
- 20078 GER Lonely Aura Mew - Legit.
- 980718 JP Modest 20th Mew - Unproofed, possibly spoofed. Looks fine.
- 07157 Bold Palcity Nagoya Psychic Mew - Hosted by Project Pokemon. Looks fine.
- 07157 Serious Palcity Yokohama Barrier Mew - Hosted by Project Pokemon. Looks fine.
- 170505 KOR Lonely WCSK17 Mew - Same unproofed one I have, legit.
- 10160 FRA Lonely AUT2010 Mew - Looks good.
- 57432 JP Modest アイコ Shiny Old Sea Map Mew - Legit.
- 10160 SPA Modest OTO2010 Mew - Looks good.
- 25192 JP Adamant Eppie Shiny Old Sea Map Mew - Legit. Comes from Eppie of Project Pokemon/Smogon.
Hacked:
- 50716 Hardy Hadou Mew - Hacked. Wrong Origin Game.
- 39983 JP Modest アイコ Old Sea Map Mew - Hacked. Edited from original legit Shiny アイコ Mew.
- 06930 Sassy MYSTRY Mew - Hacked. Wrong PID Type (Edited IVs).
- 10160 GER Bold HRB2010 Mew - Hacked. Wrong Nature, 5 IV - Atk, 252 HP / 152 Def / 104 Sp. Def. Wrong Moves, Max PP Ups on all moves.
- 10160 ENG Timid FAL2010 Mew - Hacked. Wrong Nature.
Edit: Here's the second batch, from Haileo again (you're a machine)
Legit:
- 02016 ENG Hardy Takes plenty of siestas GF Mew - Looks good.
- 01000 ENG Lonely Hayley Mew - Hosted by Project Pokemon. Looks fine.
- 02016 ENG Hardy Somewhat vain GF Mew - Looks good.
- 07157 Quirky Palcity Fukuoka Transform Mew - Hosted by Project Pokemon. Looks fine.
- 22796 JP Impish ORAS JP GameFreak Virtual Console Mew - Looks good.
- 10160 GER Gentle HRB2010 Mew - Looks good.
- 10160 ENG Timid FAL2010 Mew - Looks good.
- 07157 Mild Palcity Sapporo Amnesia Mew - Hosted by Project Pokemon. Looks fine.
- 03219 Bashful NoK Mew - Looks good.
- 07157 Serious Palcity Osaka Ancient Power Mew - Hosted by Project Pokemon. Looks fine.
- 07157 Lonely Palcity Makuhari Mega Punch Mew - Hosted by Project Pokemon. Looks fine.
- 60510 Impish Pokepark Mew - Looks fine.
- 11219 Modest Susumu Mew (Second Distribution) - Looks good.
Hacked:
- 50716 Hardy Likes to thrash about Hadou Mew - Hacked. Edited from original Hardy Loves to Eat Hadou Mew.
And his third batch:
Legit:
- 01000 JP Brave Yukari Mew - Same one I have, legit.
- 01000 ENG Lonely Hayley Mew - Hosted by Project Pokemon. Looks fine.
- 01000 GER Mild EUKALIA Mew - Looks good.
- 01000 ITA Calm GIULIA Mew - Looks good.
- 01000 FRA Brave EULALIE Mew - Looks good.
- 03219 Bashful NoK Mew - Legit.
- 980718 ENG Brave 20th Mew - Has video proof, legit.
- 22796 ENG Calm HKTW Pre-order GF Mew - Looks good.
- 06930 Calm MYSTRY Mew - Same one I have, legit.
- 11219 Adamant Susumu Mew (First Distribution) - Comes from me, legit. I traded this to someone on January 2.
- 01000 ENG Bold Hayley Mew - Legit. My self-obtained Mew. I traded this to someone on January 2.
- 01000 ITA Adamant GIULIA Mew - Legit. I traded this to someone on January 2.
- 10160 ENG Careful FAL2010 Mew - Legit.
- 06930 Rash MYSTRY Mew - Touched, legit. Same one I have, but mine is UT.
Hacked:
- 01000 SPA Lonely EULALIA Mew - Hacked. Wrong OT. Supposed to be Eulalia, not EULALIA.