The fixers at Wadi Halfa are related, uncle and nepphew I think.
Ask in town at the hotel for the 'helper' for the vehicle barge, or drive to the Customs shed at the port (about 5 miles from Wadi Halfa town) and ask there. You will be introduced/directed to one of them. I think one was called Magdi, the other had a similar name I think.
Their charge was 50US for a car, 40US for a bike. Including all the taxes.
I don't know where the tourist police office at Aswan port is. (In Nuweiba it was next to the ATM in the port compound). But if you ask for 'Tourist Police' you'll be shown their office I'm sure.
Our policeman dealt with the importation of three vehicles together and we tipped him 100 Egyptian pounds. We've heard of 30 or 50 for a single vehicle.
We've had no security issues so far. Here in Khartoum and Sudan in general it seems as safe as houses. There are lots of police always around, some alarmingly-armed by British standards (tripod-mounted machine guns on the pavements!)
In Khartoum at night it's dark - no street lights or lights from shops, but plenty of taxis.
It seems Sudan, in the north anyway, has a reputation of being one of the safest African countries to visit.
As a foreigner you're instantly recognised and welcomed by everyone, in a caring way. Sudanese want foreigners to visit their country.
And as a tourist you'll find it difficult to travel to any dangerous areas.
Ditto Egypt, where in Sinai and some other areas the movements of tourists are constantly logged by having your Egyptian number plate noted at all the checkpoints.
Also in some areas, armed police guard all hotels where foreigners are staying.
So it feels pretty safe everywhere. In one hotel we even had a policeman wrap himself up in blankets to spend the night right next to our motorbikes!

Don't know how you're getting from Egypt to Cyprus, but if via Syria, children in large groups can be troublesome. If adults are around they will shoo them away for a while. But then you'll have to contend with them yourself if you're still there (waiting outside a shop for instance), by keeping them occupied or they will get bold enough to start to try to 'borrow' things they can get their hands onto.

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TTR250 - London to Cape Town