Hi there - good luck with the move.
Q1 - sounds right. If you are on a B permit, tax will be withheld at source and as your combined income is over the threshold (and I assume you are married to each other) you will complete a tax return each year and receive a refund (or additional bill) for the difference. There are tables which will tell you exactly how much will be withheld from your respective salaries based on the tarif (probably "B" in your case) each month.
www.steueramt.ch
Q2. You are correct. It will cost at least that much for full time care of your child. This is because rent and staff costs here (salaries, pension, insurances)
are expensive here and the daycares have much higher costs. There are also strict building & fire regulations to be adhered to maintain a licence and this can mean a big investment of cash up front. Thus the higher costs. I know this business and daycares charging this much actually still have low margins. That is the reason for the shortage of them too. See
www.kinderkrippen-online.ch for information about availability of child care places.
Q3 Again, what you state for a family of 3 sounds right to me. There are ways to get it down by increasing your so called "franchise" or insurance excess as we know it. THis means you meet a higher part of the up front costs yourself. That is what I do, but with a child (and potentially frequent visits to the doctor) this may not be the right solution for you to get the premium down. See
www.comparis.ch wher you can compare premiums of different companies.
Q4. This can be okay or a nightmare depending on the particular building you are in and the neighbours. You could ask when viewing apartments if you could install. You would be expected to return the apartment in the exact same condition you found, or the renters who take it over from you, take over the responsibility for removing the washing at the end of their contract.
Q5 - how long is a piece of string ? There are many great places in Kanton Zurich to live and this is a very personal decision based on where you work and availability of child care & schools in the area which you choose. Here is the property portal which has alot of additional information on this topic.
www.homegate.ch &
www.sbb.ch or
www.zvv.ch will show you how long the commute will be from the properties which you like the look of.
Enjoy your time here. It is a wonderful place to live and bring up children.
Post again and let us know how you get on.