* I'm hoping to start August 1. I assume there is not a snowball's chance of it being processed in time for that, if it is lodged end of this week?
it depends how fast you submit them all the documents, and they usually take about 6 to 8 weeks for the processing after you will submit your all documents, they may have some queries at later time and you must fulfill all first before you could be issue with a visa.
* My wife has applied for a new passport as her old one was expiring next year. We thought it best to get a new one while still in our home country. If I submit her details, do I use her old passport numbers, because surely those change once she gets a new passport (only due for delivery in a month's time). Same with my 14-month old kid. She has a temporary passport and her proper passport will only be ready in about a week's time. They both will follow me only when their travel docs are ready.
you can always apply with her old passport and just add one letter for the immigration officer stating that her new passport appication is under process. As her existing passport is less than one year valid, so immigration will wait til you can get a replacement passport for her. otherwise they will cut short her visa. usually visa validity can be one month shorter than the passport validity. However, if her existing passport is more than a year then even they issue a visa label on her old passport , you can use the visa label on the new passport, just make sure her particulars are the same on the new passport and also nationality is the same,. i.e. dont use SWiSS passport when you have applied the visa on British passport.
* Do they each also get a sticker in their passport once my work visa is approved.
they have to apply seprately, they will only be issued visas once your visa will be approve as they will be dependent on you.
* Are the visas sent to your home country's HK consulate?
there is no Hong Kong consulate anywhere in the world. Usually visas will be issued directly from the Hong Kong immigration officer in wancahi Hong Kong upon prescribed payment, however if you will specially request them then they will forward the visas to your close Chinese Embassy or Commission. I suggest dont do that, Chinese embassy is alwasy NOn-systamatic, they will definatly waste your two to three weeks time with no reason.
* Could I enter HK without my work visa to set up place to live etc. even if my visa has not been processed?
i have no idea what passport do you hold? I assume you hold south African or British passport. you can always come as a toursit and get your home etc matters done if you are sure that you qualify for the visa. And once your application is approve you can go to China to activiate your visa label.