Congratulations on your first mod! It sounds like you've made some great modifications to the New Holland FR780 harvester from the base game. Adding main color and rim color configurations, a sticker configuration template, interactive control points, and multiplayer passenger seats are all valuable features that can enhance the gameplay experience for users.
It's perfectly normal to encounter some warnings and issues when creating mods, especially as a beginner. The important thing is that you are actively trying to improve and fix those issues in future updates. Learning through trial and error is a key part of the modding process, so don't be discouraged by any challenges you encounter along the way.
Community feedback can be helpful in identifying areas for improvement, so feel free to seek advice or suggestions from other modders to enhance your skills and make your mod even better. Keep up the good work, and I look forward to seeing how your mod evolves in future updates!