I am pretty familiar with ETOPS procedures so no need to do specific research. All aircraft are built (at least newer aircraft) with some out of the box ETOPS ability but not certification. ETOPS classifications are 60, 90, 120, 138 and 180 minute rules and yes they have nothing to do with over water but rather airports within the time limitation that could handle an emergency situation for that aircraft type. All aircraft and operators by definition have a default 60 minutes ETOPS. SA have on 90 minute ETOPS their 319s and 120 minutes on the 738s. You are correct about the liferafts.
ETOPS has four components: 1) engine health monitoring, 2) predeparture service check, 3) system maintenance practices and 4) event-orientated reliability programmes. In order to move from the default to a higher certification you need to satisfy all four components. One can satisfy 2, 3 and 4 generically (i.e. independent of aircraft or engine type) but one cannot satisfy point 1 without an operations history. You are required to operate the engine type successfully to gain certification and this is very difficult to do quickly with a small number of aircraft. It took SQ 6 months to get 180 ETOPS on the 77W and this only occured so quickly because they had a number of birds and a history with the 777 and engine types (by the way the 777 default is 120 mins). With 3 birds and an unknown engine and aircraft type it should take SA.
Whatever the CAA issues are with ETOPS SA will have to satisfy FAA requirements as well.