For FTTP, isn't the starting point more usually described as the head-end, or the NGA Handover node, rather than an exchange?
Yes, this node is normally in an exchange building.
However, I don't think there is a definite path from "Main Exchange" to "Local Exchange". The Local Exchange might be missed out entirely, have no head-end equipment whatsoever, and have none of the fibre routing that way.
The relationship between exchanges, in an FTTC/P context, is more often described as parent/child - where the child doesn't have the head-end equipment or handover node.
However, while the child's cabinets may be served by fibre terminating in the parent's active equipment, the fibre itself doesn't necessarily route via the child exchange building. Take a look at this old thread
Here's three factsheets with diagrams, though with different emphasis on internal/external detail:
However, you'll probably find this link the most interesting, architecture-wise:
Presentation to BCS, on NGA Deployment Strategy, 2011
So, I'd do:
FTTP: Parent Exchange HO OLT - AN - Splitter - DP - Manifold - (X) - ONT - Router
FTTC: Parent Exchange HO OLT - AN - FTTCcab - PCP - (SCP) - DP - NTE - Modem - Router
ADSL: Local Exchange HO - DSLAM/MSAN - PCP - (SCP) - DP - NTE - Modem/Router
(X) - is the external splice tray on the premises. Not sure what name is given to this.
(SCP) - Some copper lines have a second cabinet in the path.