They won't use names of people in the airport descriptors, it would only be locations like Mascot or "Western Sydney." IATA has very strict rules against this (there are some exceptions obviously like JFK), but the idea is that these names are often chosen for political reasons and
I am not familiar with ICAO rules specifically but I can't see that many ICAO names use the personal / honorific names. Also, there are a lot of "YS" that are not in Sydney so don't think it's that strict? (example YSGE , YSPV, and YSPT in Queensland, YSRN in Tasmania, etc).
Talking about ICAO. YSSY is called SYDNEY / KINGSFORD SMITH.
The S in YS is not Sydney city, it's Sydney FIR (which no longer exists) and loosely covered all of NSW & ACT. Refer my post where I explained this - if it was a two letter navaid, the first letter was the FIR - B (Brisbane), P (Perth), S (Sydney), M (Melbourne). That's why Hobart is YMHB, Alice is YBAS, Darwin is YPDN and Canberra is YSCB. The entire country was split between these four FIRs.
Only Brisbane and Melbourne FIRs exist now, but the historical FIR codes still exist. The two letter codes, whilst out of fashion now, still exist, most recently when YBMC (MCY) changed to YBSU.
There are a lot of three letters that start with B, S, P and M so that letter (as in YSPT) is not necessarily the FIR letter.
I would imagine, unlike IATA, ICAO do not get involved in individual code assignments, and leave that up to the respective countries - since unlike IATA the ICAO codes operate a bit like a domain name, where Australia owns all of Yxx_ and USA Kxx_. The USA has its system of assigning codes (K + FAA code, which is often but not always the IATA code), Australia as I described above.