Because the brief simply says an SLR and A.N.Other camera with no other info, I'd choose my OM-4Ti and Trip 35 and hope they covered all my bases.
But in real life my choice would be guided more by specifics of the shoot that I would inherrently know in advance.
E.g.
Street shooting: 35RC primary, Trip 35 as a backup
Landscape photography: OM-1ɴ primary, OM-4Ti backup
Formal portraiture: OM-4Ti primary, OM-1ɴ backup
Family gatherings/informal shots: OM-2SP primary, OM-40 backup, both in Program mode with auto-winders
Sports photography: OM-2SP in Program mode, OM-4Ti backup, both with auto-winders
On safari, miles from civilisation and fresh batteries: OM-1ɴ primary, Trip 35 backup