Yes! Hopefully your colleagues are learning from you a new way to do data science! I use a combination of IDE and Jupyter Notebook and they obviously each have their benefits.
Yes, ULMFiT is not well known in the NLP community. Unfortunately, ULMFiT is not as flexible as other models as it is a unidirectional model, but for a sentiment classifier, it is probably fine. I wish you luck.
You probably already know, but huggingface has their amazing pytorch-transformers repository. There is some discussion here and here for using the repository with the fastai library.
Kaggle is very different in this respect. In Kaggle you try your best to improve more model, even by 0.1%, even if requires a 8 GPUs LOL. But based on your experience it seems Insight is focused on developing solutions that can be implemented and used in the wild!
Good luck on your project! Thanks for sharing your experience!