Depends on size. If they are quite large and been in for 5 years, i thiunk that there isn't miuch chance. If they have been in for a year or two, then maybe yes.

You need a big a root ball as you can get baring in mind that you will have to be able to easily carry and move to your new house. Now is the ideal time before it leafs, but would of been best to dig around the plant in autumn severing roots, and then lift in spring.

What height are they? Trunk size? etc and how long been in soil?

If the sale has been agreed and you didn't stipulate that the trees were not included, your buyer is expecting to buy the house and garden in the condition that they saw it when looking round, so legally speaking, you shouldn't take them unless that has been agreed.

The root ball is normally at least the size of the top growth so looking at the trees will give you an idea of the depth and spread that you will need to excavate. The trees plus rootball are going to be very heavy too. I think it might be better to leave the trees to grow where they are and plant anew when you move into your new home.