Most of them in the Peak.
THe DfT hasn't yet decided where those 5 Adelantes are going - several TOCs have bid for them, including FGW. IF they arrive at FGW, then they are NOT going to all be allocated to the Oxford / Cotswold services - they might get one or two shoulder-peak trips - but elsewhere (?Mark Hopwood has said one might even end up one of the branches)
Other than needing a refresh and staff some training, they could go straight into service, definitely won't wait for a timetable change.
And the turbos - they'll all stay with FGW - at last some much needed strengthening will take place - and no, that plan isn't anywhere near complete yet, as there's no guarantee the 180s are coming to FGW yet.