I want to get feedback on (1) fertilizer / wood ash and (2) pruning as it relates to 2 eastern white pine seedlings I planted.

CONTEXT:
I planted 2 eastern white pines, each about 1.5-2 ft tall, in my yard spaced roughly 20 feet apart receiving almost full sun. I am located in western-central Illinois (southern portion of zone 5) on a Lake - one tree is +/-8 feet from the shoreline and the other +/-12 feet away from the shoreline. Both are around 5 feet above water level. The area surrounding the lake is dominated by old growth Oaks, however, there is also a very strong population of eastern white pines that were planted in the 1950s - 1960s that are performing exceptionally well so I am comfortable assuming this area grants better than average growing conditions for the species. My yard also has several sycamores and sugar maples that are performing very well.

SOIL/FERTILIZER:
When planting, I made the mistake of mixing up potting soil so I accidently covered the surface of the planting area with wood ash from our fireplace. I am aware of the alkaline effect of wood ash which is not ideal for an acidic-seeking pine. I am unable do anything physically to correct the mistake until 7 days following the application so I have 3 questions:
1. How long does it take wood ash have a noticeable impact on soil ph?
2. What kind of remediation should I look into? My initial thought is to remove as much of the ash as possible, replace with soil and needs and add an evergreen fertilizer.
3. Does anyone have any experience with eastern white pines and wood ash?

PRUNING & GROWTH:
Assuming these are able to grow at a normal rate, I am looking for feedback on how to prune eastern white pines properly for nurturing healthy growth. My goal is to prune the lower branches as high as possible (ideally while they're young so cuts can be grown over) to guide a straight and uniform trunk, but also want ensure I am not over pruning and inhibiting the trees. I've had success pruning maples and other deciduous trees pretty aggressively while they're young where it really improved vertical growth, however, I have no experience practicing this with pines so want feedback if this concept is even applicable.