1. Guo Yizhan: Personally, the last word sounds crisp and neat, which is easy to leave an impression;
2. Guo Lushuo: It's a bit of a detour, and there are many strokes. It's hard to sign in case you are in a hurry;
3. Guo Yixuan: It sounds good, but it is used by many people, so you can adopt it if you don't mind.
4. Guo Lukai: Combining the questions in 2 and 3, it is not recommended.
I'm just talking about my personal feelings. I hope it will help you. It's sometimes easy to make a simple analysis, and choosing a name needs humanization. Haha!