Regarding your architect's comments that sites on estates...

Regarding your architect's comments that sites on estates are built on at various and random stages only occurs if the lots aren't pre-purchased and/or pre-designed. A principal contractor may choose to stagger the development if it is a massive estate but generally the schedule is as follows:
1. Earthworks
2. Roadworks (Ret Walls are generally done at some point between 1 & 2)
3. Stormwater
4. Water Reticulation & Sewer
5. Landscaping
6. Construction

Also keep in mind that there will be (in theory) multiple Hadrian's working on lots during stage 6. From the videos we have seen on the Hadrian, as long as Stages 1-4 are done and the slab is down, they can operate. I imagine that FBR work with the principal contractor (GP Vivienda) or EPCM who will ensure that X number of slabs are down on the lots before the Hadrian's are mobilized.

Hope this helps.