John or others with experience,
I familiarized myself with your recommendations, but wanted a complete, concise list of steps since you seem to offer advice in other posts more specific to the issues the poster has.

I have already done:
1. Chemically stripped previous homeowners failed stain off.
2. Applied brightener/neutralizer
3. Sanded as appropriate
4. Applied 2 coats TWP 1500 (wet on wet)

To Do:
5. Oxalic Wash: Is oxalic wash needed before the a coat if it is only a few weeks since the original coat was applied or just before a maintenance coat years down the road?
6. Apply TWP 1500 wet on dry: I want to build coats as you recommend to minimize the need for maintenance. When should I reapply the next wet on dry coat? (some posts say the following spring, others a few weeks)? Just 1 coat, correct? Next one to be applied when needed or proactively on an annual basis?

Also, I noticed some spots seem to be lighter than others. Is this something to worry about or is it possibly due to sun exposure in this area already?

Thanks for clarifying. I can assure you that the community is grateful for your wisdom.