Golden Hollows
A mysterious old-world relic, the Golden Hollows hold the secrets of Mayan civilization; and the evil organisation that wants to strip this land of its resources.
BuzzSaw
The BuzzSaw name and theme wouldn't need to be altered all that much. This ride becomes base camp #1 of the company's illegal logging campaign. I think minimal physical theming in the way of tents/marquees, log bundles and logging equipment/machinery can be added to the entry pathway to the ride. The sign can also be changed to reflect the unwelcoming nature of a logging camp. Stylised "Keep Out" signs, etc.
Deity's Revenge
The Mayan God of Flora wants revenge for the attempted destruction of its once-prosperous lands. Its statue can be seen standing over you as you enter the queue line.
The ride area closest to BuzzSaw features an active logging site. Smoke rising from hot spots, sparks flying from chainsaws. An exaggerated site. Trees "falling" and a lot of audio cues around the launch track. While the other half of the ride where the reservoir used to be will have plenty of greenery, a few Mayan-style archways, totems and ruins.
Totem
Unicoaster Flat Ride
The centrepiece of the ride themed is a totem tower. Ride chosen because it follows Dreamworld's latest trend of User-choice ride experience. If you want to roll, you can roll, if you don't want to, you can remain static. The ride would be shaded by a selection of triangular leaf-coloured shade sails. This ride placement is shown in Dark Green on the map and would sit on part of the RHLR course.
The Temple
Chute the Chutes (Log Ride)
What would arguably be Dreamworld largest single capex spend - this immersive chute the chutes ride would have the longest ride time in the park; also boasting the highest capacity. (Although, it's not like it has any competition at this point, right) Majority of this ride will be indoors, to allow for show scenes focused on simple light and audio effects. (Nothing over-the-top, the concept has to be slightly reasonable right?)
The entry plaza would be lined on both sides with taller trees, creating an enclosed walkway - forefronted by a Mayan style arch with the ride logo. The end of this walkway (which includes a new wider bridge over the railway tracks) is a foreboding forced perspective Mayan temple - the queue house. Left side for queue entrance, Right side for viewing bay/exit.
Left side of this area, towards the car park/old BB amphitheatre would be indoors, this acts as a noise barrier to the car park and M1, while the other half of the ride would be meandering through dense jungle. The main drop on the ride would be of similar height to RHLR, and would be present on a faux volcano. The final homage to the areas that preceded it.
Giant Drop and Surrounds
Demolition of the entire raised walkway section, including existing ride queue. Signalised train crossings on both sides of new pathway. Ramped queue line entry/exit path wraps around front of GD building and utilises front of GD for overflow queue/main entry.
Area where raised pathway used to sit will be a campsite with a small retail offering. Much like what the Log Ride store was. Drink + Ice Cream Fridge and a few small souvenir items. Offers ride photos for surrounding rides. BuzzSaw, Deitys Revenge and The Temple.
The Red Circle is of course a large, reasonably tall directional sign.
The Log Ride area I haven't gone into because with the restrictions you've laid out, I don't think there's reasonable demand for more F&B or Retail without further area development. A good-size family rollercoaster would definitely be perfect for that area though. Train station can remain where it is, log ride queue can be transformed into a static seating area. Pathways don't really need reconfiguration.
(Thanks for giving me something to do this morning )