Can someones romantic orientation and sexual orientation be very different (aromantic pansexual or asexual polyromantic) or do they have to go in hand (aromantic asexual, biromantic bisexual)?

If you feel it, it is real and valid. We separate the types of attraction because they are so different, and many people have different orientations for each of them. While most people label no more than their romantic and sexual orientations, anyone can have a different orientation or all types of attraction -- aesthetic, platonic, romantic, sensual, and sexual. With the number of different people in the world, we can near guarantee someone out there can define themselves as panaesthetic, polyplatonic, biromantic, homosensual, asexual. Some people even have opposing orientations, like heteroromantic homosexual, or have fluid sexuality that changes regularly. Whatever set of labels feels right, is right, even if that means having no label or making up a new one.

They can absolutely be different! Your sexual orientation and your romantic orientation are two separate things. Even if they statistically are more likely to go hand in hand, almost ALL combinations are possible here. :)

No , they don't , it's not the same thing at all! An asexual could be panromantic and a pansexual could be aromantic

The romantic orientation and sexual orientation of the person need not go in hand, it may be different. It's all about the preferences in the end.

Of course not, for example, I am a hetroromantic asexual. Romantic attraction and sexual attraction are different which means they do not have to match each other, sometimes they do, sometimes they don't, it depends on the person.

They can absolutely differ! And the amount they differ, can be extreme or very slight. Someone can just not experience one form of attraction, but still very much experience the other, and that's okay. That's why the terms are separated now - it's not just one word description.

They can be different, you can be bisexual without having to be biromantic; just because you're attracted to a certain gender etc sexually doesn't mean you are romantically

Romantic and sexual orientation do not necessarily coincide. Any combination of orientation is possible, and they can also be very different, like the example you mentioned. That's totally alright, and it's always possible to find a lifestyle and relationships that fit the way you feel!

Of course it can my friend is pan romantic but identifys sexually as lesbian so it doesn't matter your orientation is your orientation no one can change that

They can be different. Not everyone feels both romantically and sexually attracted to people.