The mountain ash you can probably replace from a local nursery.
If you are patient you should try grafting for the Cherry and Apples. Take several cuttings of the year old sticks now, and keep them in a ziplock bag in the fridge.
Order some rootstock, most is picked over by now unfortunately so good luck, from Raintree, Cummins Nursery, Treeco, etc. Then graft onto the new rootstocks per the videos above. (I did a couple videos on YouTube, and Stephen Hayes is good too)
Abundant Design on YouTube
If you are impatient, you can buy bigger trees from your local nursery in varieties of your choice.
If you want to try to save the trees you can try bridge grafting
Bridge Grafting on YouTube