Hi, For the 17/1.8 I'm pretty sure it's much lower than $600 currently with the previous cashback promos by Olympus SG

ask around a bit , unsure let me know ; at least u won't get chopped.
For EM1 body, if u don mind , one can obtain a set from Qoo at $1049 + $25 delivery but buying from which source is really up to oneself as I have bros who insist on buying Leica from Leica while some insist on buying from 2nd hand shops. Or one can pick up a almost brand new set from BnS prob at really good prices now.
The 5 axis on the EM1 is crazy enough for me to shoot sharp holding it in one hand with a heavy lens (Nocticron 42.5) and other hand holding my baby. Yes I used the word crazy because it's true.
I've tried Sony A7 (lens with OSS) , Fuji (almost all the bodies and their primes) and none could perform the same coming to stabilization.
The AF with high sequence shots the EM1 is fast enough I've shown some bros (subzero and alfie) here the reason why I never really use CAF. It's seems u have the RX100iii which is already a very very capable camera , if u don't mind EM1's size and weight , my suggestion is go for the EM1 since I remember u mentioned u will go for the pro level lenses too which are heavier & need better balance.
The 14-42EZ is one of the sharper kit lenses on the MFT platform (I tried the 14-42, 14-42II , 14-42IIR) but I agree that i will skip a POwer zoom end of the day.