-Rhinodon, Charge then animus, thresher before charge resolved.
-Rhinodon, Trample, then animus before resolving attacks from trample and fs.
The trample itself is a melee attack. Since you cannot interrupt an attack, you wouldn't be able to do anything there in between.
The charge works because it is split up into movement and attack. Sort of like giving an order to a unit. You do all your movements on the charges first, then you enter the next phase and go into your attacks.
The same applies to other models. Movement and attack sequence have a seperation there for abilities and triggers to take place.
But the trample is not seperated into these phases. You are sacrificing all your initial attacks to make the trample attack power. Basically, you have already begun and cannot interrupt these melee attacks.