Seeking advice for Australia trip in May

Hi everyone!

Planning of visiting Australia. Travelling with a 70 plus year old senior who may not be very strong in terms of climbing steps but could walk on flat surfaces and short distance ascend/descending.

Our interest are in natural scenery and waterfalls (big, powerful plunge waterfalls kind). The senior remembers and has been frequently mentioning one of the waterfall seen at NZ (can't remember the name) from years ago. :). And the Pancake Rocks and Blowholes at Punakaiki.

I have a driving licence but uncomfortable driving overseas.

Would like to seek advice on the following: 1) Is the following itinerary practical? 2) Will it be possible to visit the various places using day tours from operators? Any recommendations for reliable ones? 3) any recommendations for good plunge waterfalls which I may have missed out? 4) Based on online information, it seems like May will be a cool climate for travel. With the impacts brought about by climate change, quite uncertain whether information about average climate of locations still holds true. 5) for domestic flights within Australia, how much buffer time to arrive before the flight would be required? Have yet to factor in the waiting time into the itinerary.

Travel period: May, dates tbc

Day 1: Arrive in Perth

Day 2: Take a short flight to Rottnest to see the cute Quokkas and spend a day visiting Rottnest, return to Perth in the late afternoon

Day 3: Travel to Hutt Lagoon and back to Perth

Day 4: Fly from Perth to Sydney, Visit Sydney Opera House and the city. Stay in Sydney city, near to the Central station.

Day 5: Take train (BMT?) to visit the waterfalls at Blue Mountain. (unsure if taking trains and stopping at each station near to the waterfalls is a good option. Based on Google map, seems like it takes an hour plus from Sydney. Will it be accurate to say that the best waterfalls are around Katoomba station?)

Day 6: Book a day tour to Fitzroy waterfall and surroundings

Day 7: Book a day tour to Eagles Peak, Curracurrong Waterfall

Day 8: Take train to visit Kaima and blowholes

Day 9: Sydney to Townsville via flight

Day 10: Book a day tour to Wallaman Waterfalls (yet to find a tour operator who does the tour. The trip to Townsville is just so that we could visit Wallaman Falls)

Day 11: Townsville to Carins by flight, visit Cairns

Day 12: Depart Cairns