Players beginning with Skinsaw Murders - Advice

My players are tired of the "start a level one being the heroes of a small town", so they asked to start this campaign at a higher level. I think I will have them skip book one completely. My plan to bring them into the campaign is below and I would love thoughts on ways to add to it or potential hazards to avoid.

I am thinking I will make Aldern the hook. They are coming to Magnimar at his request. Maybe they have family connections or have worked with him before. The initial session can be them meeting up with Aldern while Xanesha is giving him his final task of collecting the diseased rats. They will have the opportunity to see the Scarecrow golem in the shadows.

I am hoping that they will be able to forge some sort of connection with Aldern while being able to meet Xanesha early on in the campaign. This initial meeting will have Aldern flustered but hopeful that things will be ok. Based on my players, I am expecting them to cast some doubt on either Aldern or Xanesha. Either is fine with me really, as if they suspect Aldern early I can just have them go along a "clear my name" type of path after being framed for some of the murders and if they suspect Xanesha then that is fine as well. The Aldern reveal might be more impactful and they now have a Big Bad to work toward defeating.

Thoughts on where best to work in Ironbriar or play up the Foxglove family's tragic past?

Thanks!

Book 1 really sets a lot of the foundations for the rest of the campaign. With the above you will be missing several very important pieces.

The biggest thing that book one does is give you players a chance to connect with Sandpoint and its citizens. If they come out of it caring about what happens to the city and having connections there, you did a good job. This comes back in book 2, book 4, and book 5. If you skip this, books 4 and 5 are far less impactful. My suggestion in your case would be to try and make sure that the PCs all have connections in their backgrounds to Sandpoint, family there, businesses they run there, etc.

The players will be revisiting the Ruins of Wrath in a later adventure in book 5. My players just hit that and it was a lot of fun for the three players who had characters from the original group walking the two newer players through one of their old adventure sites. When they finished the library in book 4, it was really fun when they researched more and more and found out what both the Ruins of Wrath and Thistletop actually were and then immediately started piecing together hints they had been getting since the beginning of the AP.

If the group is starting at level 5, I recommend starting with the short Shattered Star tie-in module "Dawn of the Scarlet Sun" alongside skinsaw. Kasadei (the cop) could be a great contact for the PCs in Magnimar, and you can keep your Aldern clearing his name angle.
Zadendi is a freelance murderer hired on by Aldern, she splits the kills for herself and the greedier ones for the Skinsaw cult etc. When the party deals with her and discovers this, they can chase him down at Misgivings, and continue as normal from there.

As Sean mentioned above, there's alot of links to Sandpoint within the first 4 modules, not just in Book 5 with the Ruins of Wrath. For instance book 4 has a defend Sandpoint from a Giant attack, etc.

You can minimize or ignore Sandpoint and just play the start of the AP as a Giant (literal) threat to the region in general. Maybe Kasadei hires them on to investigate the authenticity of the threat before Magnimar commits resources to help Turtleback ferry and Sandpoint and go from there into the impending awakening of a Runelord. In this case, you can even have Sandpoint attacked in the background, they defended... but at great cost.

GL

In my view, the first module does two things for the campaign as a whole, 1) Introduce the town of Sandpoint and all its NPCs and get the PCs to care about it and 2) Have the PCs explore the Catacombs of Wrath and get a sense that Sandpoint is built on top of Thassilonian ruins.

These can both be accomplished within the Skinsaw Murders module. Have the PCs arrive in town to investigate the murders. You might have to do a bit of rewriting of the module to make it more of a mystery who the murderer is (in the module itself the PCs can figure out it's Aldern pretty quickly). But with a more robust whodunit the PCs can get introduced to the various NPCs in town, the locations (including, possibly, the Catacombs of Wrath). The Scarnettis, the rumor that Chopper is back, etc. can provide a lot of red herrings.

As Sunderstone mentioned, Book 3 ends with the PCs learning of a Giant Attack inbound to Sandpoint and Book 4 begins with the PCs fending it off. If the PCs don't care about Sandpoint, the rush to defend it and the epic battle to save it have less of an impact. It's one of the high points of the campaign and having interacted with the guys at the brewery makes it all the more dramatic when the giants destroy it and possibly kidnap the brewers.

The Catacombs could be encountered in The Skinsaw Murders, or you could wait on it. The Giant Attack in Book 4 is for one of the Baddies to see if the thing he is looking for is in the ruins under the town. This will get them curious about the Thassilonian ruins around town (although the Old Light will generally attract interest), but I don't know that you couldn't just encounter the Catacombs when the sinkhole opens it up in Book 5. There's just a cool moment in Book 5 when you go back to the first dungeon you explored in the campaign and there's relevant stuff beyond a corridor that was blocked the first time you came down there.