The builder is Janez Velkavrh, our customer near Ljubljana. He is very pleasant, not a professional straw-bale builder, but according to my communication with him, I got a picture of a real nice men who could be willing to share his experience with straw-bale building with you. As you can see on the picture, he also had a lot of diagonal timbers which are crucial for structure stability, but had enough patience (and working hands) to do excellent and amazing job. My opinion is that this is the best (and cheapest) way to buld wooden structure home with walls of straw-bales. I didn't spoke with him about floors, but I think he didn't isolate it with straw-bales. However, according to last three drawings you posted, you will never have any problem with the straw-bale moisture in the floor, because it is - uh - like ventilated.
Regarding to your budget, I think that 150.000 is way too enough to finish structure like on the plan, just be very carefull with picking cotractor or wooden structure subcontractor, and you will be fine. Maybe Mr. Janez had good contractor or subcontractor, so he can refere you to one.
Here is Mr. Janez's contact:
Janez Velkavrh
Stara cesta 34
1354 Horjul (Ljubljana)
His telephone numbers are registered, so ask Informations to get one (I did the same way). Be free to bespeak my personal best regards to Mr. Janez, and I think he will be willing to answer any question you need. V Slovenščini bosta lahko pogovarjala o vseh Vaših težav in vprašanjih...
Best regards,
Bane M. Prvanovic
GPB Solutions d.o.o.
Celopecka 8
11000 Beograd