Just about all the items I have left to collect are related to Blaire's shop. I have the wedding recipe which can't be completed because I don't have recipes for two of the ingredients. I have played for hours without the shop advancing. I've completed all the other synthesis available, cleared Mull's Dungeon 3 times so far. I'm only missing 16 items and 14 of them are directly related to Blaire's shops.
I've done the sidequest where I talk to Villa and give a candy to Blaire, but there hasn't been a follow-up since then. I've tried talking to Hute, and everyone in Arcos. Any ideas on other things to try?
I also haven't been able to trigger "Delsus Secret Skill" in Lake Forwell or "Saving Pekli" in Kavoc. I have managed to unlock Mull's Dungeon and Zeldalia's Test for Norn without having finished the game on this save
I had a problem with Norman that was similar to the one you're having with Blair. He wouldn't offer the Smartini recipe even though I had made every other item in his store and beaten the game. He finally offered the recipe after I raised the quality of some of his other items, so maybe you could try improving the quality of Blair's other items.
Also, what two ingredients are you missing for the Wedding Cake, Cheesecake and Tiramisu? Blair has the Cheesecake recipe, but I'm pretty sure it becomes available after the Wedding Cake recipe. Tiramisu is a recipe at Mofuma's in the Hidden Village.
I did the quest for Delsus's Spirit Blast skill about midway through the game either a little before or after the party's first trip to the Land of Mana (I think my party members were in the low to mid thirties). If you haven't triggered it now, you may be out of luck. I think I read on one of the archived topics here that it's missable. Did you find the letter for the old man, Zazzy, earlier in the game? That may be a prerequisite for the Spirit Blast quest.
I triggered the save Peki quest during the event where Kavoc was under attack. I had completed the quest where you give Lyla a vacuum cleaner a little earlier in the game too, but I'm not sure if that's required. This quest is actually pretty annoying because it repeats every few hours and the rewards aren't anything you can't find elsewhere, so you're not missing much.
Most of Blaire's recipes are already maxed. The ones that aren't need rarer items than I've used (Dunkelhite for example).
Tiramisu depends on Blaire's Caramel Cube which is missing. Cheesecake is also a missing recipe.
I have done the letter quest fairly early on. I haven't gotten Noisy Hagel yet, a prereq for Save Pekli. I think it requires 6 StringAcoustic in the inventory, and I may have been too late in the game when I got it.
As I write this, I had left the game unattended for 4 hours. Then I did as you suggested and bumped the quality on a recipe and tried a few other things, left the store, spoke to Viola, returned, and I got the test event, which added 5 recipes!! I saved in another slot and reloaded to see if I could play around with it.
Here's what triggered the event: I went to the RosieAnn BunA recipe and put in the ingredients for RosieAnn BunB (a recipe I already had), and after closing the conversation and re-opening it, the event happened again.
After making those new recipes and having Snickerdoodles in my inventory, Delsus Secret Skill quest event occured (before the Blaire finished the test event).
Ok, cool, I'm glad it worked out. Don't lose any sleep over the Save Peki quest, all it does is provide you with a relatively easy source of Baji Serums, Dunkelhites, or Dragon Horns. Since you only have 14-16 items left to make, you probably don't really need many of them anymore.