1) I'd thought Cleo might be without Iron now, but she could get it as well from an ally. In any case, having an Impi sit on a source would prevent her from using that source on a flip.
2) WE will need that source to upgrade our warriors before joining them to army. That's why I won't pillage any of the two before we have upgraded them. Of course keeping Heli is healthier because it has barracks which are essential for the upgrade...

3) Imagine Heli flipping the Interturn before our warriors go there

- or even worse the turn we upgraded them
Maybe we better upgrade those warriors near Umfolozi there? That's the safer way...

4) We could need Iron to do that...
fastest way to Iron would be building a colony near Swazi or Ngome next turn...
5) BUILDING that army should take place immediately, to encourage some more luck in the next turns

. I see a reg osman horse approaching. More to follow? Best lure for leader fishing...
6) I would place that empty army on a mountain fortified with some defense...