I've got about as much experience with both PF1 as PF2 but I've got more experience with 4E than either, so I'll give it a go.
I think you've got to have a Warlord in the party. One of their main functions worked off of action points, which are a little bit like hero points in PF. Main thing is that when they use them, they get another action and they boost their allies in some way or let them take actions. For PF, this would be as easy as giving them an ability to 1/battle let themselves and all of their allies move or attack for free. Then you'd also give them the ability to heal self or allies within 30' 2/battle (but make sure when you describe it that it's like the ally was inspired to be healthier and is clearly not a magical effect). On top of that, many of the Warlord's at-will abilities were to help an ally move or attack. Easiest way, in my opinion, is let them replace an attack with an inspiring shout that lets an ally make a weapon attack instead (using the ally's reaction). Give the ally a bonus to damage equal to warlord's Int.
4E Paladin could mostly be a fighter but I'd give him the ability to use Divine Challenge (as a cantrip) and Divine Sanction (as a spell). Both would impose the shaken condition but only if the target is attacking someone other than the paladin. If the target attacks an ally, the Paladin uses a reaction to deal 3+CHA(+Level?) damage to the target. Divine Challenge is a move or swift, and targets only one creature. Divine Sanction targets every hostile creature in 30'. Also, challenge has to be applied every turn (ends at end of next turn), sanction continues until the target takes damage from it. I'd probably let them use divine sanction twice at most. In 4E, this was radiant damage. PF analogue heals living creatures instead of damaging them, right? So, maybe switch it to fire or maybe untyped, or just say it deals damage instead anyway?
I'm not sure what the other characters should be off-hand. You definitely want a controller in there. There were some really weird ones if you want something strange, like the Ranger (Hunter) and the Invoker. I always preferred Wizards in 4e for controllers but I can't think of anything particular interesting to do with them in this setup. I'd suggest Visions of Avarice be a spell that they have, if you do go wizard. Basically puts an illusion in the middle of a 25' radius area. The illusion is tailored to each creature in the area, being whatever it is they desire most in the world. They have to make a saving throw each turn or be drawn up to 25' to the center of the area. The spell's flavor has always struck me as really cool, though in practice it was basically a "those guys over there don't get to do anything while we rain artillery on them" kind of spell.
As this is a 4e party, there should be at least one of every role. For the striker role, I'd suggest either an avenger or an assassin, as I think they're the most unusual of the striker classes. Avengers are divine damage dealers. They imply an "oath of enmity" condition 1/battle that lets them roll twice and take the high, with a conditional damage boost depending on their choice of "censure." Censure's had conditions such as "if your oath target walks away from you, you get bonus damage until end of next turn." Meanwhile, Assassin's main neat thing was the shroud mechanic. Swift action 1/turn to put a shroud on the enemy, up to 4. Whenever you attack, choose whether to invoke shrouds. Get bonus 1d6 damage per shroud on a hit, or as much as one less shroud on a miss. They could also teleport between shadows and turn into an insubstantial cloud of darkness.
Everyone in 4e could do opportunity attacks during every other creature's turns, so maybe just give them all combat reflexes or bonus reactions some other way to keep it simple. Another thing you might do is put weird effects on the various characters attacks (if they aren't full-attacking), to replicate the way at-wills work. Stuff like moving a hit enemy 1 square, or dealing extra damage if a damaged ally is nearby.
Maybe someone who knows PF1 better than me can take the above and refine it into something more directly useful.
