Can You Get Botox, Fillers and a TCA Peel in One Visit?

I see your concerns are valid with respect to the forehead lines.
There are 3 forces creating facial wrinkles although some wrinkles may have more than 1 contributory force to varying degrees:

aging & sun exposure of the skin - cheek skin wrinkles in the elderly, adynamic wrinkles
chronic muscle action - crow's feet, horizontal forehead wrinkles & vertical wrinkles between the 2 eyebrows, dynamic wrinkles
weakened supporting tissues with age & the constant forces of gravity - the jowl wrinkles on either side of the chin

Botox only works on the muscle contribution to wrinkle formation (dynamic wrinkles) & the more muscle action contributes to a wrinkle the more effect Botox will have, temporarily. If the wrinkle cannot be effaced with finger pressure prior to botox injection the injection will be less effective because the problem is then permanent damage to skin layers. This is unaffected by muscle paralysis. Looking at your photos it looks like the forehead lines have been present awhile & are deep with skin changes i.e. thinning in the depths of the wrinkles. I doubt they will efface or disappear when spread apart by finger pressure and so will not completely disappear after botox injections.
I don't know how old you are but doubt you are past 40 so it's more likely that the forehead wrinkles are due to the way you personally move the forehead muscle along with exposure to the Australian sun than to forehead drooping.
Botox will likely smoothen the forehead lines but not completely erase them-you waited too long and the lines are too deep. I can't see what you hope to achieve with a TCA peel as the skin pigmentation is even without blotches and have virtually no adynamic skin wrinkles.

Yes, Botox cosmetic, injectable facial filler, and chemical peel may all be performed in one office visit. The decision to perform all the procedures depends on the patient, cosmetic specialist, specific filler & peel, and areas treated.
For example, one may choose to have nasolabial folds filled with hyaluronic acid, use Botox cosmetic for Crow's feet, and have a superficial chemical peel with light-strength TCA. There are advantages and disadvantages to combining procedures. However, the procedures may not be combined if more extensive. Only after a comprehensive evaluation by a plastic surgeon or dermatologist can he/she may an appropriate recommendation for you. Best of luck.