help for picking up the right box

Hello every one,

Long time user of kodi i’m looking for a box to replace my dune bdprime 3.0.
I’m tired of using yadis to keep my interface in sync with my database.

The dune is plugged in the living room on my main tv and i want to replace it. I have some needs which i explain below.

My tv is an old sony 46W3000 but i want to be ready when i’ll replace it with a 4k.
My A/V receiver is also old. It’s a yamaha RXV14000 (no hdmi). I will replace it soon probably with a yamaha with hdmi support (RX A850 or similar)

The remote control is a logitech harmony one (will also probably be replaced with a harmony elite)
My media files are shared across the network by a synology DS1815+ which also run tvheadend with a usb pctv73 stick. I will probably add a hdhomerun as 1 tuner is not enough for the bunch of devices i have.
The nas is also running mariadb with phpmyadmin for my kodi database (jarvis version). I have several devices using it: an apple mba with el capitan and jarvis, a rpi2 with libreelec 7 on a second TV and a zetaly android tablet with the android version of jarvis.

To sum up my needs i have to find a box with:
-hdmi 2.0
-4k output ability for the future but with full 1080p support for now
-hevc decoding
-ir receiver for being controlled by the harmony remote
-spdif output to be plugged into my A/V receiver. Or at least the possibility to use a hdmi switch with audio extractor until i get a new A/V receiver.
-i’d rather have a box with libreelec (i like this distribution)
-i don’t need retro gaming
-i mainly watch mkv with srt subtitles, bd-iso, dvd-iso

For now it seems that odroid c2 is a good choice.

I have subsidiary question: i’ll reuse my harmony one with the rpi2 as hdmi-cec is quite limitated. Have you a suggestion of an ir receiver fully compatible with the rpi2?
I read the forum but i’m quite lost with the ton of devices listed here.