First of all - you want to do everything right the first time .... good on you!
Your father-in-law's qualifications are not relevant here - he can't build anything structural legally without the council permits and a local licence. This is not to say his skills are not excellent or are unworthy of respect .... a crafts-person is a crafts-person no matter where they're from or where they happen to be now.
If you are only doing cosmetic work that doesn't involve structural alteration to your building you do NOT need permission from government UNLESS it impacts some kind of 'order' like heritage, place-of-special-interest etc.
that said, I am not about to recommend you proceed with any work without telling your body corporate, except to say this - I have always been more inclined to ask for forgiveness than permission, especially with people who seem to enjoy their power a little too much.
It is impossible to know if the quote is unreasonable without knowing the amount of work required, but I would struggle to find ways to spend $17,000 on labour in 8 square metres of space. Something is wrong. I have been thinking a lot about "what is reasonable" when calculating costs ... I made a fridge cabinet recently for which I charged $5200. The client happily paid it but her brother thought it was a rip-off and told me so. After explaining to him precisely where the money went, he apologised but I understand where the confusion can lie and take no offence in any way .... we think fridge cabinet and think it is a couple of bits of melamine-coated MDF with a thing along the top to join the bits .... the fridges never fit properly and we learn to live with that. In this instance I had a very specific brief that required me to design a cabinet that was not only beautiful, respectful of the Edwardian period and of course, fully-functional but would last for generations. I designed it, bought all the materials to make it, made and painted it, installed it which required considerable modification to the "new" plastering work that had been done on the walls (it was way out of plumb) ... the entire job took 3-4 weeks to do and materials cost about a thousand dollars. I doubt anyone today would grudge me making a thousand dollars per week, less running costs - heck, my plumber charges $90 per hour and gets it day in day out. Of course, if I invest around $400,000 in reasonable machines I can make things a fasterbut I can't design, assemble, paint and install faster even after that. It's fun!
Replace the power point - why leave a ratty old one after doing all that work?
good luck!