waruikazi
Legendary
Personally? Very little. Still plenty of stone country, still plenty of places to hide from intense wildfires (crevices, caves, monsoonal vine thickets), still enough small mammals about for a large python to feed on every six months.
I also don't imagine ferals preying on Oenpellis is a big problem - apparently they are really hard to find? As for toads and your tall stories of wounded carpet pythons, anecdotally, all of the wild Oenpellis I've seen eating toads were fine...
Still enough small mammals for a large python to feed every 6 months? I hope you're not basing that on anecdotes! Now even if there is still enough small mammals, birds etc for them to feed every 6 months, how would that effect them if they are meant to be feeding every 3 months? We are getting in to the realm of hypothetical questions but i think they are relevant. A reduction in prey items will have an affect on population dynamics.
When there are researchers like John Woinarski (and he's not the only one) claiming that the reduction in small mammal populations and habitat for the reasons i already pointed out, is a threat and likely to have an affect on this animals population i think we need to listen. I don't think fires and feral predators are having a direct impact on their numbers, but i think it is very likely there is an indirect impact.