Nathan, welcome. I'm only an amateur veggie grower so I'm sending you an e-mail to suggest some extra help.
Your soil sounds like its a fantastic base for growing. And your ideas to enrich it further are fine I think you just made the mistake of overdoing it.
Even though things like mushroom compost and cow manure may say "composted" they may still have some breaking down to do. Both are intended more as soil improvers. In future it would be better for you to prep a veggie patch well in advance to allow it time to settle.
I think you have had a couple of things going on. Firstly you have "transplant shock" as seedlings are introduced from punnet to the soil. Up till then they have been grown in a sterile environment with plenty of misting and some weak fertilizer to get them at peak size for sale.
You have then put them into a fresh environment, which you have just mixed up, of a large mix of organic material, the combination of which may have been too rich, too moist, PH either too high or too low, or other elements that the seedlings just weren't used to.
On top of that, I think your area has had some real heat recently, which also would have set them back.
Better luck next time, it's all trial and error and we all had a start that way. What fruit trees are you putting in? You might get some advice from the nursery where you bought them, or asking your new neighbours about recommendations.

Hi Nathan, I reckon Alisonoz is probably right, and that your plants are suffering from over kindness and fertiliser burn, meaning the fertiliser is too rich for the plant roots and is kind of burning them.

I always water my seedlings every day and sometimes twice a day if the weather is hot, too. You might be able to save some by flushing the fertiliser through with lots of water, but it might be too late. Don't give up though! Nothing like fresh vegies, especially tomatoes!

Heya Everyone :)

Thanks for the time to email me and the information. Its given me hope ( Yay! ) I appreciate the advice :D thanks!!

Seems like my special mix may have been overkill then.

Sooo....im going to mix up a trailer load of mushy compost, manure etc and leave it sit outside for a while to rot a bit and then try again. I think ill try different methods and see what happens.

I bought a probe today :D and i can test for things like light, PH, and a few things, then ill be able to get a better idea what types of soil mixes I have made.

Alisonoz , i had that in the back of my mind too about transplant shock and your right in that we have had some horrible heats here which is unusual for the area, so the combination along with the fertilizers was probably overkill...

The fruit trees i bought are varied species of Pair, Grape, Apple, Peach, Nectarine, Cherry, Berry, Plumb, Mulberry and Nut trees. Some are varied species so im told needed to cross pollinate (I think it is called?..) also got a couple of other fruits Ive not seen or eaten before ( cant recall the fruit name on those ).

Anyway i hired an excavator, got some pretty big holes dug out about a meter or more round and 2 meters deep ( at least ). I put each fruit tree into its hole making sure the trees were not too low or too high - but just right as they were in the bags
(had to back fill the holes to get the level right but the ground got a good churn in doing that).

I have planted about 20 fruit trees now, cant recall the bag sizes but they were like 25 , 50 , and I think 75 liter bags ??
(mixed sizes). I just went crazy and bought a bunch of trees.

I also bought a bunch of other things outside of the fruits like weeping willow Crab Apple, Japanese Maples etc to spread out around the land.

All the trees were planted in 100% soil - i did not add a thing at roots level on any tree, but once planted I did use that same mulch mix that I used for the vegies on top of the ground around each tree.... .. .. Ill keep and eye on the trees and see if they begin to look sick or anything, most of the fruits had small fruit beginning to grow at purchase.

Well thanking you all again for the messages and pm`s. I really appreciate the time to reply to me with help :D

I have a feeling Ill be back lol - but I hope with good news :)

My best
Nathan.

Nathan it sounds like you've done plenty of homework already, I reckon you'll go OK.
A tip with seedlings (transplanted ones esp) is to give them a bit of shelter for the first few days to a week while they gradually get established. Otherwise, as you say, there can be too much stress when they have no decent root system, and then they are hit by heat or dry winds.
When I was young and there was bushy scrub around (not environmentally threatened) we used to cut branches of stuff like tea tree and stick small tufts of leaves in a group round a seedling to give it a bit of shade. The scrub would die off eventually but just go on the compost heap. If you have time/energy you can make up little hoop frames, or even triangular tunnel frames and cover them with something like 50% (at least) shadecloth - then can be placed along rows of the tenderest seedlings for a little while. The idea is to create a shade that won't blow over or sag down in rain and crush the plants. If you google images of "plant cloche" you will get the idea of the SHAPE (but cloches are for covering seedlings to protect them from cold - you WON'T use plastic/glass or similar for YOUR seedlings or you'll fry them - but it might give some ideas as to how to rig up a bit of shadecloth - even some offcuts.