My first question is...will 1 r/c be enough for you n your kids ?
Sounds like the slash will fit what you want just fine, its low and wide
so it will be stable, very durable, and wont break the bank !
If you have fairly clear trails or paths in the woods then 16th scale will do ok.
But If its rougher and more rugged terrain then id go for the 10th scale.
If racing is in the future then id say 10th as well.
Good luck and keep us posted.
And Welcome to RCU