(i) Consider Mr Keene and Mr Uzuma fixed at the two ends of the line. This leaves 9 people to arrange in between them. The number of ways to arrange 9 people is given by the factorial of 9, which is:

\(9! = 362880\)

Since Mr Keene and Mr Uzuma can switch places, we multiply by 2:

\(9! \times 2 = 725760\)

Thus, the number of ways is 725760.

(ii) Treat the 5 Keene children as a single unit and the 2 Uzuma children as another single unit. This gives us 7 units to arrange: 5 Keene children, 2 Uzuma children, Mr and Mrs Keene, and Mr and Mrs Uzuma. The number of ways to arrange these 7 units is:

\(7! = 5040\)

Within the Keene children unit, the 5 children can be arranged among themselves in:

\(5! = 120\)

Within the Uzuma children unit, the 2 children can be arranged among themselves in:

\(2! = 2\)

Thus, the total number of arrangements is:

\(7! \times 5! \times 2! = 5040 \times 120 \times 2 = 172800\)

Therefore, the number of ways is 172800.