The very fact that the Chinese factories who produce Jazz for the Chinese domestic market have invested now to produce faclift versions of the Mk4 body shell with new front ends etc suggests to me that an all new Mk5 is still some way off.
But it may be more complex than that.They might know that Honda would manufacture an all new ,significantly different mk5, in Japan for the Japanese ,and some other, markets first , with China only getting it later.
Years ago it was quite common for manufactures to continue production of obsolete models in overseas factories for years if they considered it was more suitable than newer more complex models for the local roads and garage infrastructure .. . A decision largely made by cost accountants 'back home' IMO than any actual local knowledge. . This probably no longer applies to China, who probably have a better infrastructure for EV's ,technology etc than many other countries but still might not get Hondas latest model straight away.
Of course any success with one of these syling facellifts might influence the actual mk5.