The first one you need an SFP/SFP+ module (pic upper right 18.89Eur). The other, you don't need one, just plugin the cable (Pro:simple no other cost, Con: can't customize/upgrade later with better sounding modules like Finisar or an AOC cable from Cisco.
If you choose the upper right FMC, then yes. Any SFP/SFP+ module can do. Problem is what type/protocol..your fiber cable will depend on it for connection.
Answered above
Yes, and shortest LAN cable possible to your R26.
Depends, in my system, I say aboout 10-15% level up
Will cost you only around 15Eur (for a Jameco Reliapro). Unless you go for exotic types.
In my system, It smoothed out the edges, black background, more texture.
Pair 10Gtek FMC + SFP module combo
0,5m Single Mode SFP Fiber cable, Duplex LC-LC 9 (lenght is dependent on how far is your LAN cable too your DAC)
JAMECO RELIAPRO 5V/1A
Around 95Eur total
Others, please confirm module and cable are ok (think so, I have different modules)...tnx in advance.