I would recommend soppa365.fi for your recipe needs. It compiles recipes in Finnish from several sources. You can usually find something that works with little to no adjustment.

For the sweet lörtsy you can use any Lihapiirakka recipe, but shape it flatter, replace the filling with apple jam and cover the whole thing in sugar at the end. The finished result should be floppy, the name kind of indicates that too.

The savory version uses meat, but I found this with a quick google-fu. You can probably use the same dough for the sweet Lörtsy.

https://www.soppa365.fi/reseptit/kasvis-vegaaninen/lihattomat-lihapiirakat

As for the blueberry pie (eat with vanilla ice cream/vanilla sauce of some kind): https://pakkopulla.vuodatus.net/lue/2007/04/ruis-mustikkapiiras

A couple of things to note: Nordic "blueberries" are actually bilberries, which are more tart and more ibtense flavoured compared to the blueberries grown in the US, but those should still be good enough :) (https://youtu.be/8zcQyWeZtX4)

Butter here is basically always salted, so use a bit of salt in the recipe if you use unsalted butter.

Here's a couple of pretty common resources for traditional recipes, search is your friend.

https://www.valio.fi/keittion/

(Search by vegan) https://www.valio.fi/reseptihaku/?haku=vegaani

https://www.k-ruoka.fi/reseptit

Here's the traditional "mustikkakukko" aka "rättänä" recipe

Kukko's are foods from eastern Finland / Karelia that are baked inside the crust. Kalakukko is basically rye bread with fish inside and lanttukukko with rutabaga and meat. Vegan version of lanttukukko is made with seitan and tastes great!

While making Karelian pies you can also check out this "sultsina" recipe, they use basically the same dough and filling

https://www.greatlakesgazette.com/2013/06/01/finnish-nisu/

Lots of Finns in the UP, you might add Upper Peninsula to your search for recipes in English.

I like rössypottu myself - a specialty of the Oulu region. But since you're a vegetarian, the blood pudding (veripalttu) might not be up your alley.

https://www.k-ruoka.fi/reseptit/rossypottu