Little bit of someone else’s Eucalypt isn’t worth the bother, let them sort their own shrub, it’s a fussy firewood.
Leylandii can be a pain, but those aren’t too big. Sned them standing, start burning brash, fell them, lop tops off as you go and sling them on the fire too. Should have a load of 8′ cord wood out of that. Stumps will be a pain though.
In 2 days we cleared a bunch of Leylandii from around a colleagues cottage. Approximately 10 ton of firewood left for them and a brash pile in the meadow that was bigger than their cottage. Had the benefit of a tractor and winch as well as the experience for a few stunt fells.