My friend is using a recipe for Sgt. Pepper's tea that involves powdered morning glory seeds and fresh peppermint.
1. The recipe involves brewing the tea, then straining off the leaves. (2 tbsp of peppermint per 8 fl oz of water)
2. Then soaking powdered morning glory seeds in the cold brewed tea with some lemon juice overnight and then straining the seed mush off before drinking it. (300 seeds)

What negative effects would arise if you were to just blend everything up in a blender all at once and drink it?
This means without straining anything off or letting it soak.

If done this way, you don't waste any LSA or acetaldehyde in the peppermint or morning glory seeds.
You don't have to worry about the mixture fermenting or LSA deteriorating over time.
It's just blend and drink when you're ready to dose.

Besides the strange flavor and texture of the drink, what problems might he run into?

Stomach ache and vomiting at least strain the tea first you will feel better.

...and chemical reactions do not usually just happen spontaneously. I presume you're trying to make the elusive LSH from LSA and acetaldehyde; it is wrong to assume that LSH can form as quickly as blending and gulping. Maybe leave the blended mixture in the fridge overnignt then strain and drink.

Thanks.