Questions re living in Dar (Dar es Salaam)

Hello, please could you let me know what you think of the following:

-is it necessary to have the garden sprayed with insecticides? (not sure whether we will get a standalone house or an apartment)

-I might arrive in April next year, has anybody arrived/lived through a rainy season in Dar yet? I will arrive with 2 small children and am not sure if it's wise to arrive then, or sit out the rainy season in Europe first..

-what precautions do you take on a daily basis regarding drinking water? boil, filter? Or do you buy bottled water. What about the bath water for a splashing baby, is it too dangerous to drink bugs in normal tap water?

-Do you know of any German Kindergarden or school? I have found nothing on the internet yet.

-Do you buy mainly in supermarkets (which supermarket names are there please), or do you buy from local markets?

-Is there an average wage for cleaner and nanny? Is it common to have a live-in nanny, or are they mostly live out?

I'm trying to get my head around living in Dar - we know West Africa and SA so far.
Many thanks for your replies.
Sylvia