we’ll be seeing you

Need context. In the meantime, I can say that in general, "We" means more than one person, so that "We'll be seeing you" would not mean the same as "I'll be seeing you".

However, the other people need not be present. For example, imagine you came to visit my family -- which would be nice, because you sound like a nice person -- and when you left to go home, you said goodbye to my family and I came with you to the railway station, I might say, "We'll be seeing you", meaning not only me, but my mother, my sister and my brother as well as me, even though those other people were not there.

PS Where I live, there are now many Polish people who have come to work, and the shops are full of Polish food products. I have become addicted to Kabanosy. How can I stop? ;-)

Yes, 2 million Poles have left the country, because of unemployment here and opened job markets in the EU.