RE: Which Engine for Pattern
That aircraft, at a rough guess will probably weigh at least 10-11 lb and will most likely need an engine weighing 32 - 36 oz to balance. That pretty much removes all choices you are considering except the OS 1.60 FX and 1.40 RX.
FWIW, in this part of the world at least, guys are typically using the OS 1.40 RX with a pipe or the YS 1.6 or 1.7 for 2 metre competition.