Thina middha and Sotapanna

First, PLEASE provide a link to the post that you refer to. I believe the following is the post that you refer to:
“Key to Calming the Mind – The Five Hindrances”

“1) I have seen this claim that Thina middha goes away at Sotapanna only from you so far. Do you have a source or some more information on it?”

You have not seen it discussed like that because most people do not know enough Dhamma to realize that. There may not be a Tipitaka reference for each and every issue. There are some things we can deduce based on other related evidence.

“2) Even a Sotapanna must have some laziness or drowsiness, right?”
– Your question is based on the assumption that thina middha means laziness/drowsiness. That is not so. Please read #9 in the post in question.

I will try to expand on the above post to provide more info, probably after I finish the next planned post.

After thinking about it, I think it may be a good idea to have a separate post on five hindrances within the new series of posts on “Basic Framework of Buddha Dhamma”

But the main point is that “thina middha” is a hindrance.
– On the other hand, thina and middha are TWO SEPARATE cetasika (mental factors).
– When they appear TOGETHER, that is a hindrance to comprehending Dhamma.

The same is true for uddhacca kukkucca.

I have revised the post, “Key to Calming the Mind – The Five Hindrances” but will provide more details in upcoming posts.