Hello Dan,
The link you are referring to is about the Electronic Bank Statement/Lockbox - this functionality is actually changed/extended by the EA-FIN switch (see also note 1121965).
But I would not consider this as a part of SAP Treasury and Risk Management (->EA-FS).
Concerning the switches
FIN_TRM_CORR_FW (-> new correspondence functionality, see note 1338244),
FIN_TRM_LR_FI_AN (-> EhP3) , FIN_TRM_LR_FI_AN_2 (->EhP4) and higher EhP switches:
yes, they are optional and each of them comes with extended functionality-
the respective release notes give an overview
(SAP Support Portal -> Release & Upgrade Info-> Release Notes...->
SAP Solutions - SAP ERP - SAP ERP 6.0 -> EhPs).
Hope this helps,
Marie