Hello.
I just viewed your attached files, and this projects is really complicated.
My opinion to prepier all files in Autodesk Inventor will take about 35 days, and 5 days to found all mistakes and carefully review all files.
If this 40 days is to long, I can work with my brother, he is also professional CAD designer.
Long story short, my daily CAD designer work is really boring, and I searching more complex work, such as yours.
If we talk about price, so my opinion $9000 is really enough, but freelancer.com charges you $10000.
But if you have some problems with this, I think we can correct price.
When I work with similar projects, I like to have place, where I can keep all files (cloud, server or something), because you and my have easily access to all files.
When we have place where you can upload all drawings, only then I will start to analyze all drawings, and if needed asked you some explanation.
So after few days of reviewing drawings, I will start to make 3D models.
Also I saw that these scanned drawings have patent in Australia, I really don't want to take responsibility if you break some patent agreement.
My opinion payment have to be divided in some stages to maintain motivation. (Please look at milestone)
5 day after we start $ 500
15 day $2500
25 day $2000
30 day $1500
35 day $1000
40 day $2500