In my honest opinion I don't think that the 10 step procedure you described can work out; what I mean is that you have to find an employer who is patient enough to wait for you to complete the whole immigration process, which would probably take months. Given the fact that the high demand in Structural Engineers is an outcome of the Christchurh Rebuild Project which is not progressing as expected and the fact that it is expected to accelerate sometime in 2013, potential employers would need you ASAP. Also and in regards of you working from home, while your imigation process is running, I don't think it is realistic. Just put yourself in their shoes; would you agree to work with someone whom you have never met, he is in the other side of the world whilst he is not familiar with the NZ building code? (there are just too many unknown factors in the above equation). Don't want to discourage you, these are just some thoughts from someone who is in the exact same situation. Maybe there are other forum members with different opinions or experiences
But there is a workaround (at least I think so).
Why don't you go for a temporary work visa once you have a job offer; this way you have a job offer, then have your qualifications assessed by NZQA and finally apply for the temporary work visa, which is fairly quick (I' ve read in this and also in other forums that there are people who managed to get their work visa in a week but to be on the safe side I believe that it will take about 2-3 months, including all paperwork, medicals etch). So the above could be stage 1,2,3,5,7 and 6 of your process. Note that by holding a Work Visa you are eligible to sponsor your family. There are of course some disadvantages with the work visa, for example you can only work for the employer you signed the contract with and you have to reapply before your visa expires, but you can always apply for PR whilst you are on a working visa.
Now about finding a place to live before moving to NZ, I believe that your actual presence in NZ is mandatory for you to find a decent place to live. My plan, if I ever find work in NZ, is to first go by myself settle and after 2-3 months my family (wife and 2 kids) will follow.
Job opportunities expo is indeed a good chance to meet employers and I will definitely think about it.
Regards
Zach