Since you're in melee anyway for champion reaction, you might actually get real value out of marshal as opposed to bard, though even then I'd retrain that to bard at 12 to take advantage of lingering dirge of doom.
For your other issues:
1) learn and take heal as a signature spell
2) pack anti-ghost items (there are tons), silver sheen and get cold iron weapons. This solves most issues with physical resistance.
Thanks for the feedback. Just to be sure, you think Bard MC would be the strongest pick here? And if you had access to both Fear spells and good demoralize, is Dirge still better than something like Inspire Courage/Defense?
Fear is two actions, costs a slot and lasts 1-2 turns. Demoralize only works once per enemy and has other requirements. They both need to contend with enemy saves. Lingering dirge is a 3-4 turn AoE fear that costs a focus point and can be used again if a fight goes past the lingering duration. Given how unreliable getting enemies to fail anything is, circumventing enemy stats entirely is preferable.
That and heroism is better for status bonuses with its longer duration
Right now, I'm nearly a 6th level elemental sorcerer (earth) about to poach the Champion's best 3 things: heavy armor, lay on hands, and the reaction. The rest of the party is:
1. Scoundrel rogue
2. Infinite Eye psychic
3. Bo staff, i.e. strength, monkWeaknesses I've seen in our few encounters together are:
1. Fragility. People go down a lot and my Battle Medicine/LoH are at their limit keeping people up. Thanks to the Champion MC's Heavy armor, my caster's AC is the highest.
2. Helpless in the face of enemies with physical resistance. Not much the rest can do at that point but soak hits, which puts me in a rough spot of choosing between ending the encounter with my sole access to other kinds of damage, or keeping them alive before it ends them.With one class feat, my options coming up are these:
1. Choose a low-level sorcerer feat, though I think there's not much there after Reach and Primal Evolution. Dangerous Sorcery is the best I can find, and the extra damage seems negligible.
2. Invest even more in Champion MC with either Desperate Prayer or Resilience.
3. Start another dedication.Of those, which do you think would best help this party?
One of the other characters should pick up battle medicine so you don't have to heal every round. All 3 of them have the hands free to do it.
You don't have to heal them unless they go down. Maybe they are being a bit too agressive.
A Rogue should be able to handle some physical resistance. The Psychic has damage options and should have at least 2 different attack cantrips. Even the monk can get an alternative damage type in their Ki Strike. It shouldn't be all on you.
Heal is well worthwhile taking as a signature slot.
Champion is not that compelling once you have got the basics - which are fantastic BTW.
Are you playing Free Archetype? If so then maybe Bard is a good MC option. It is the best caster MC as it has great feats, good low level spells, has the least overlap with Primal spells, and no difficult attribute scores.
If not then there is enough really good stuff in Sorcerer to stay in class. Level 6 is not that great if you don't like your 2nd Bloodline power - the Greater Bloodline power at level 10 is important for an elemental sorcerer.
The extra damage from Dangerous Sorcery is small, but it adds up. You should take it. Reach and Widen Spell are worth it. A couple of the level 6 Sorcerer feats are useful but they aren't the standouts that Primal Evolution, Bloodline Resistance or Cross Blooded Sorcery are.
One simple addition will give you all a great advantage; get shield block. For one general feat, you can have a repeatable damage reducer. In my experience playing so far, that bit of damage reduction every encounter does wonders for preventing the need for in-combat healing.