CE on Supports

It's up to you, but if I had your servants and CEs, I'd probably go half and half. For example, do you really need to offer your friends 3 different bond point CEs? If someone is just looking for a support with a bond point CE, then they're probably more interested in the CE than the servant, so they don't actually care which servant has it. In that case, they don't really need a choice of 3 different servants with bond point CEs. Might as well just offer one bond point CE and then put combat CEs on the other two servants.

And there are a few servants that probably should always have certain CEs. For example, Heracles should probably always have his max bond guts CE on. Raikou should probably always have Kaleidoscope on. Personally, I probably also won't ever borrow an AOE saber that doesn't have Kaleidoscope, but that might just be me.

When I farm Mana Prisms (by completing once 40 AP & farming 30 AP EXP Card daily quests) I'm looking for MLB Chaldea Lunchtime / Heroic Spirit Portrait - regardless of class and/or being friends or not
When I do 40 AP QP quest I ofc go for Rider with MLB Mona Lisa
When I do free quests / farm any kind of item (both on daily quest or free quest) I also prioritize MLB Chaldea Lunchtime / Heroic Spirit Portrait. Of course sometimes there are quite hard free quests so I must be smart not economic so I choose the most powerful servants
When I do main quest... it depends. If it's something easy (in my case a few Lancer/Assassin mobs) I go for our glorious bond raising CEs
But if it's Grand Battle or something harder (like last 3-4 chapters of Camelot) I go for servants with "normal" CEs

IMO you should keep this setup until Christmas. On Christmas ofc swap CEs to event ones.
When Christmas ends we'll looking forward to Babylonia and I think this is the time when you should put down those utility-CEs and go for metagame essences

Sorry for my English but I hope you understand what I mean ^^'

I see some of them aren't MLB I'd recommend not equipping those I mean people aren't going to want to take 2% extra when they could just refresh the page and find someone offering 10%. I would recommend kscopes or MLB IEs on people with AOE NPs that might be good for farming. Other than that just make sure that people are equip with a CE that synergizes with them.

Put lunchtime to Waver is quite a good idea. Honestly speaking, people are more using Friends` caster class servants. Typically when there is no event or new chapter released. Even for new chapter, many player still need farm bond point.