Did you do a Session 0 to figure out the role the characters are going to play in the group? Do the backstories connect at all to the campaign and the other players? If not, I'd really suggest you back up and give all the players the opportunity to make characters with the goal of synergy.
I did yeah, two of them assumed they could do a full multiclass at some point and it didn't really seem like an issue to not have a solid healer at level 1, but it seems that isn't the case.
As an example, let's say you have a 7th level character with Dex 14 and Trained Thievery. Assuming regular gear, they will have a Thievery bonus of +11. A typical level 7 trap has a Disable DC of 27, so the character needs to roll a 16+ to succeed. Oh wait, no they don't, because you don't even get to try unless you're an Expert. And I mean sure, you can retry, but it's still to the point where you wonder why you even bothered investing a rank in Thievery.
I'm not sure how they're going to work around it without a rogue or other character dedicated into it. They did a low level dungeon and were still getting wrecked by traps and blocked by locks.
You might consider providing the Free Archetype option; it doesn't overly boost the linear capability of characters, but would allow someone to go off into the Medic Archetype or maybe one of the magical healer ones without hosing down their core competency.
That is an idea, I sort of am looking at a similar thing.
With no Fighter you also lack someone who can make it harder for enemy's to move around, so enemies can and should run all over the map brutally hitting the PCs, flanking them, tripping them, shoving them, grappling them, and more. And if you do that - multiple PCs will take heavy hits every fight. Not only is it perfectly easy for a moderate challenge enemy to one-shot your wizard - they can run right past all of your group's other PCs, do it, then run back out on their third action...
I thought the paladin could fill that role but I'm seeing he's a bit different. It's a little annoying that I basically need to tell at least two people they have to play either fighter or cleric. It makes some sense composition wise but not everyone is so flexible in what characters they want to play.
So you've actually got more issues here than just no combat healing. Groups can handle having no fighter or no cleric (or other healer), but lacking both means you will either have to play with kid gloves or TPK them a few times.
I don't know what to do about a TPK. I asked them what they wanted to do about character death and said they shouldn't be able to die unless it makes story sense, or they mess up badly.
I'm trying to work with the rogue to make him into a cleric that is a "shadow cleric" with a custom doctrine around stealth, and making him an assassin of sorts.
Shadow Cleric Doctrine (working title)
First Doctrine (1st): You’re trained in light armor, and you have expert proficiency in Reflex saves. You gain the rogue dedication feat, and may select a relevant skill. If your deity’s weapon is agile or finesse, you gain the Deadly Simplicity cleric feat. At 13th level, if you gain the divine defense class feature, you also gain expert proficiency in light armor.
Second Doctrine (3rd): You’re trained in martial weapons. (Might change it to 1d4 sneak attack, even though it's normally 4th level, or a free rogue feat)
Third Doctrine (7th): You gain expert proficiency with your deity’s favored weapon, simple weapons and unarmed attacks. When you critically succeed at an attack roll using your deity's favored weapon, you apply the weapon’s critical specialization effect; use your divine spell DC if necessary.
(didn't work any further until I learn the system better)
He worships Norgorber, so he can't heal until level 2, with versatile font. But it seemed the best way to get him to play cleric and still feel a bit like a rogue early on. Deadly simplicity is a little op on a short sword, making it 1d8, and getting it buffed to 2d8 with magic weapon, but he loses 1d6 sneak attack.
Some people want to switch to 1E, but It's a good deal more complicated, and they're already new to 2E. So I mostly advised against it.
Also, the Inventor didn't have enough time to play regularly (only one session per two weeks) and we're basically down to 4 players now.