2nd layer under melody?

[Altissimo]

hello I am here again with another musical question. here is an upload (that I did because nobody else has uploaded it, which is also why the video is shit quality) of a theme from Hamtaro: Ham-Ham Heartbreak. It's pretty much the same as a theme from Ham-Hams Unite that I already arranged, except transposed from B major to E-flat major. However in the transition from GBC to GBA music there were a couple of changes made, and one of them is that there is a harmony line accompanying part of the introduction, in the same rhythm as the melody, that I'm having a bit of trouble with. Here is the PDF link to the theme in question (directly transposed from the other one I arranged with no edits, hence why the bass line is all wrong); the harmony can be heard for the duration of m. 2. I can hear that the first three notes are G, moving up to A-flat on the fourth and back to G for the fifth (aka beat 2), but after that I get a little lost. They can't really continue down in 3rds because then the downbeat of m. 3 will be an E-flat in the melody against a C in the harmony when it's clearly an E-flat major chord and therefore C has no place, but I'm not good enough at hearing harmonies to tell what's going on there. D: Any help?

(also I'm sorry if I'm making too many topics with strictly musical questions in this board, but I'm not sure where else to put it lol)

Edit: Listening again, it sounds like the harmonies actually continue throughout most of the loop sequence. I'm hearing something like this for the most part, but any comments would be helpful :p

Editedit: I think I figured out the first part of my own question - parallel sixths not thirds as seen here. That being said I could still use a look over the harmonies in the loop section :p (edit x3: also I think there are harmonies in m.1 but I dunno about those either)

(by the time I figured this all out I was like "well maybe I should just go put it in my arrangement thread and not have an entire help thread dedicated to something I actually figured out on my own" but I can't delete topics lmao)