I've began my dive into plant propagation. I've read the basics and cutting and how there are hardwood, semi, and softwood cuttings. I have a few questions about a few specific plants that I'm working on, a few region specific questions, and lastly a questions about which plants I might need to graft to propagate correctly.

TL:DR - Can I make Fruitless Mulberry, Raywood Ash, and fruit trees from cuttings only or do I have to graft them to keep them strong? How to water cuttings? Why can only certain plants propagate from softwood cuttings?

Plants in question about propagation are the following:
Boxwood, Waxleaf Privet (Japonica texicum or whatever), Ash Tree (Raywood I think), Fruitless Mulberry, White Flowering Chocolate Vine and vines in general, White European Birch, Fruit Trees, Eucaplyptus trees as well.

Of these plants which will work with SW cuttings? I've basically done what I think a SW cutting is with all of these and put them in the sand just hoping they'd ALL work, but I figure a few will fail. The ones that don't why is it that certain plants don't work with SW cuttings but do with hardwood? Is the only way to truly know just trying it with each one?

As far as location and conditions for propagation, I know you typically want something around 70*, humid, out of sunlight, I use Silica Sand so it's moist, misting every now and then, and keeping the sand moist. So being that I'm in Mojave desert (southern California) I figure that keeping my cuttings inside a white plastic bag might allow them to get too hot, is that a worry? Should I have holes in the top of my bag? Do I need to water my cuttings often if they're in a humid environment? Is misting and watering the sand and have it drain through the same thing, or do I need to do both of them separately at differing intervals? Would this work without the bag and a consistent watering schedule of the sand to keep it moist or is there a huge advantage to keeping the cuttings in a humid environment?

I understand the generic answer is "Keep it moist and humid but not too humid or not too wet and not to hot" but preferably something more specific if there is anything specific to higher heat places etc. If not no worries.

As far as grafting and which plants don't work. I'm under the impression that fruit trees, a fruitless mulberry and certain types of other trees (I think even the raywood ash tree was mentioned by the nursery) are not able to be propagated from seedlings (and grow to be strong or something like that). Does this mean that they can't be propagated from cuttings? I know plenty of fruit trees are grown, then grafted with the apple type that it is desired to produce. They use the seedling from another type to help the apple have a strong base or something like that. Is the same true with these trees and cuttings? Do I have to cut a mulberry tree, grow it, then graft on a fruitless mulberry cutting to make sure my fruitless mulberry tree thrives, or can I just make a fruitless mulberry from a cutting? Same goes for Ash and fruit trees. If not I assume I can just make a SW, SH, or HW cutting for them and propagate as usual, is that right?

Thank you for reading the wall of text and I appreciate any advice given!