You're clearly observing closely—respect for the attention to detail.
The yellow tips on the newer leaves point to slight overfeeding, likely nitrogen, but nothing critical. The darker, droopier lower leaves could be from that too, or simply because they’re not getting much light—shading in dense autos is common. Tucking or selectively removing lower fan leaves can help airflow and focus energy where it’s needed.
Structurally, your decision to top the taller plant made sense—and interestingly, it still pushed ahead. That just confirms it’s a more vigorous, likely sativa-leaning phenotype. The other plant seems more compact, possibly indica-heavy, which explains the size difference despite same conditions.
Some late LST on the topped branches could still help open up the canopy, though don’t go too hard—she’s entering early flower now, and autos don’t like too much late stress.
And yes, during this phase autos naturally start pulling resources to fuel flower growth, so some leaf changes and minor fluctuations are totally normal.
Bottom line: your plants look healthy, you're making solid calls, and you're reading the situation well. Keep it up—no major concerns here. At least in my opinion 😜