When you move through sentinel island, you get those "cutscenes" where a totem rises from the ground. When you speak to them, you get to choose which servant to pick.
The Island tells you about the totems (and how they will appear to you) when you first meet her on the island. She also tells you that if you don't make the choices, she will select your servants for you (randomly).
From my own gameplay though, I've noticed the ONLY significant choice is between Kenneth and Hermosa (difference being 3x skill points). The rest you can pick either way.
Allan vs Barbatos - you can still use the potion of intelligence even if you picked allan. The only platform upgrade that really means anything is the skill trainer upgrade. Just get some jewelry with Master Herbalist and your potion costs are non-existent, considering you have access to infinite ingredients. The -1 to ingredient costs from the 2nd alchemy platform upgrade is not really a big deal.
Radcliff vs Wesson - practically no difference whatsoever. The two malachite gems from Radcliff are of no consequence whatsoever. There are plenty of malachite veins in ED, if you roll 3x malachite gems from all the veins, you have more gems than you can really put to use.
Igor vs Jonelath - either one is good.
