B2N2
The tan covering is the fan containment ring - probably Kevlar. It provides no meaningful acoustic dampening - it's only purpose is to catch and contain fan fragments.
The gearbox is in the core area of the engine (PW4000 and GE90 - Rolls Trent has the gearbox on the fancase), however the oil tank is on the fan case. The fire appears to be in the reverser cascades which as I noted are a carbon composite structure. Likely oil or hydraulic fluid started burning which then ignited the resin the the composite construction.
There is no fire suppression system for the fan case on the PW4000 and GE90 installations - only on the core.