Since moving to Canterlot, Donald and Douglas have become firm friends with the Mane 7, particularly Sunset Shimmer. Sunset also introduced the twins to Wallflower Blush, who developed an instant crush on Douglas. Bonding over their shared interest in plants, Douglas and Wallflower became very close and were soon dating.
The Axeblade twins are two of the biggest guys in Canterlot. In fact, only Bulk Biceps is taller than them. Donald's shaved head and Douglas' long hair set the twins apart from one another, as do their personalities and interests. When they're not working, Donald enjoys playing contact sports and talking tough, while Douglas enjoys spending time in nature and taking care of his garden.
And yes, their names are a reference to the Scottish Twins from Thomas & Friends.