Happy New Year everyone!

Please I need some advice on best way to use a mixture of Companion Vouchers and Miles Runs to fly J on long hauls and also boost tier points when not using the CV.

Profile:
Family - couple with 2 children 9 & 4
My Tier points - 285
Avios - 255000
4 companion vouchers

Places we will like to visit during a 4 month period starting in April.

From LONDON>USA(East Coast NY, NC & West Coast SEA, CA) > Canada (Calgary, Toronto & Ottawa)> WEST AFRICA (Lagos) > LONDON

I know this is probably not the easiest question to answer so will appreciate any input that helps to keep cost down, boost tier points and use at least 2 of the companion vouchers.

Thanks you!
Fortress