No. Honor 8 camera does not come with Leica branding.
Honor 8 is single sim mobile phone.
Yes, Honor 8 does have IR sensor. You can use it as IR remote control with most of appliances, which support basic IR reception.
Basis on my extensive use of Honor 8 for about 4 months, I can say that these are the biggest advantages of Honor 8.
01) Super Aesthetics
02) Superb Camera Quality
03) Good Internal Software