It's an SQ 777.
Rolls-Royce and SQ have a joint-venture overhaul facility right there in Singapore (SAESL).
Rest assured, the engine is already torn down and every rotating component is being NDT'ed. Depending on which gas path the FOD took, most likely all the compressor blades are trash...LP, IP and HP. Along with the VIGVs. Each fan blade costs $60K US, BTW.
Turbine blades...who knows. Each one will be FPI'ed to determine if they're "serviceable-used" or scrap. Depending on how many hours are on the blades, some may not be worth keeping in the rotable parts shelf, simply because their life limit would mandate another engine overhaul just to remove the time-expired parts. Ditto all the major bearings.
The inlet duct is part of the basic engine. It will have it's own overhaul and be fitted to another engine when needed.
No double engine changes for crying out loud. For one, it's an SMS issue. Do you really want BOTH engines being replaced on a two-engine aircraft? Never do the same maintenance to both engines at the same time. If, for some reason you MUST do the same mx to both sides, the same person absolutely cannot perform the mx on both sides. In order to reduce the risk of the same mistake being made to both engines and a resulting dual flameout. Basic ETOPs SMS.
Old engines/new engines...they just run at different temperatures to produce the same thrust. Don't they teach that in pilot school?