Amanda, it looks like you are basically doing all the right things. I never recommend a north exposure simply because I feel that the light quality if poor, particularly for plants like this tree. That's not to say your exposure is not adequate. I just don't know. Fiddle leaf ficus are indeed trees in nature and can certainly be grown outside in full sun. But for a plant that has never been grown in full sun, it must be slowly acclimated to sun. Otherwise the leaves will surely sunburn. I wish I had some magic to share with you, but I am just a hobbyist who has grown tropical plants for 40+ years. I have over 1000 tropical plants.

The photos simply are posted here to show you what my old, mother tree looks like, outside half the year and inside half the year. I think she is healthy and I constantly have to remove branches just to keep her at 7' tall. That "inside" photo was taken after seven branches were removed. I air-layer those branches, pot them up, and then sell those divisions.

My 25+ "mother tree" while outside, April-November

My "mother tree" while inside, November-April

It is hard to provide too much light for a Ficus lyrata that is kept indoors.

Your problems may be a result of the repotting into a much larger pot. I'm guessing that the stoneware pot does not have drainage holes and that is an invitation for inadvertent overwatering and root rot. The soil that you used when you repotted is the likely source of the insects you are seeing, particularly if you used non-sterile garden soil. Finally, when plants are moved into larger pots, they tend to put their energy into filling the pot with roots at the expense of top growth. That may be why you are not seeing much new growth now.

Try to improve the light. Scrape off and remove any loose soil that you added to the top of the original rootball. That will help remove at least some of the critters. That will also allow the soil to dry deeper into the pot. When you water, make sure not to water too heavily so water does not collect in the bottom of the pot. Be patient and don't try to force new growth with fertilizer.