[Aldric]

I would just go with the Chimera having Payload, whatever slimes you load there can still use their skills just like characters in a car. If you want the chinera to inherit a skill possessed by one of the slimes, you justnuse Modular Abilities with chip slots, your chips just happen to be slimes.
Only issue I see is that the clawed tentacle can be targeted as an individual creature which may or may not be what you want.

On the issue of controlling the lesser slimes, just make them minions with reprogrammable, now they answer to the summoner or the chimera, assuming the chimera has enough IQ to make decisions for them and it's not a Minion itself.

Bonus of using payload, if the chimera is killed, the slimes in the payload might take some damage, but would then just flow out which was one of the requirements if I'm not mistaken