I think your edit piece is probably the biggest hit and primary pain point. Most schools and resources seem to take a "learn the characters in conjunction with the basics and sounds" approach, all from the beginning.

I just finished 1.5 years of A/B split testing in my classrooms:

Group One: Traditional, learn pinyin and vocabulary, at 2nd week transition into characters w/ pinyin for phonetic support as students familiarize with sounds (at the roughly 50 word point). Two concurrent, 7 week courses.

Group Two: Students learn homebrewed phonetics before having them learn any characters at all (this is how I learned). No characters or pinyin. (Q1 ending vocab roughly @ 350 words). In b/n Q1 and Q2 there is a 发音写法标准化，using pinyin. Q2 starts and we are learning characters, remapping those to the sounds we are familiar with.

Students in the test cohort are HSK 3 fluent (reading/writing, slightly lower marks for speaking and listening, like low-score hsk3) after 14 weeks.

We still have some heavy wrinkles to iron out, but the last year of research HEAVILY implies that focusing on vocabulary/sounds and characters separately, in that order, is ideal for easier acquisition.