Welcome Richardlion! You are going to have an awesome time on this forum

You had asked so many questions, that I had to print out your msg
Herewith my advise.
Best months to visit..
I would suggest you go Aug to Sept...reason...you will have both worlds..dry and the start of the rain and thunderstorms. Also, apart from the private school, you wont have the masses with government school holidays.
What do you think of the following itinerary?
I like it, but would not stay at Skukuza for 3 nights, if you have to then make it 1, I would change that to PKop, as said many times on this forum, that is my fav camp...so many roads, dams, etc...but do include Skuk as you can drive to Lake Panic and sit there the whole day

Your bungalows look great...I would not put too much emphasis on location, each one has its own advantages...yes, maybe some are better, but as long as you in Kruger and get the camps you prefer, its great. I would however change Tamboti to a luxury tent..a bit scary walking to the ablutions in the middle of the night.
Which activities?
I do agree with what you are looking at...yes you can do a sunset/night drive from Tamboti, they come from Orpen to pick you up. A morning walk is great, you will love it..it give you a whole new perspective on being in the Park...on foot...I always enjoy a night drive at Satara, Do a morning walk at Olifants..The bush braais are awesome...sitting in the middle of the bush with the fire roaring...do it!
Catering for 28 days?
the shops are well stocked, no need to leave the park..you will pay a bit more, and might not find exactly what you're looking for..The restaurants are great and not too expensive...you can have a buffet dinner at most camps for about R120 pp...gives you the opportunity to eat something different. Many times they have some kind of venison on the menu as well.
What is your p day pp budget?
Depens on how much you drink.....I have almost a case of beer during the 16 - 18 hrs I'm awake...

I would say budget on about R300-500 per day...including all food, drinks, fuel and activities...you not going to go on a drive/walk every day...so I would say during your 28 days, you will probably do 2 walks, 4 drives, 1 bush braai (maybe 2), but then it depends on what you eat...I tend to spend a lot on food and beers...
What type of car?
I would rather look at a higher car than what you have suggested...why go for a BMW?....look at a Nissan Xtrail or even a Reanult..., but spending money is a problem, then do the ford focus or look at a corolla..the grass might still be high in some places and the extra height will definately help.
Particular drives?
Any road in KNP is good...remember, right place, right time is what counts....
No matter how much you plan your roads, it will change....it all depens on what you saw the previous day...just go with your gut and drive the road you think is best.
Camera equipment?
I just bought myself a Canon 40d, and am still very new to photography

but have been told by the experts that a 500mm lens is required for birds...I still think that what you have is sufficient..and am sure you are going to take awesome pics and put it in your trip report.
Kruger guidebooks?
The first thing you do is buy a map at the gate...(Most of them do have pics of the more common animals/birds) I also have the Sasol guide on birds...animals of KNP, a field guide to Antelope of Southern Africa...its always nice to identify a buck or bird you see....
Whatever you decide...have a great time..and I look forward to your final decision.