It looks like 80 to 90% of what you have in your pictures could be easily removed with a root style
grapple.
It's fairly easy to dig out clump brush and smaller trees up to 6 to 8 inches with that style
grapple on my 60hp MX6000, which might be a similar sized tractor as yours.
Typically clump brush have spreading roots, rather than deep tap roots, so easier to pull out enmass.
Get the
grapple down about 4 inches under the surface and just move forward in low gear against the clump to pop it out. If they are large clumps, you may need to start higher up to push them to loosen the roots...but they generally pop out once you get them loosened slightly.
For the smaller trees, you can use the weight of the tractor (your MF looks to be a solid, mid-sized utility tractor - maybe 4000# (+) if loaded) to push against the trees at about 6' up...
Once the tree is leaning, use the weight of the tractor to ride the tree down, leveraging out the roots. Occasionally you may need to dig/pry at the roots to finish getting a tree out, but they are generally loose at that point and not too difficult.
Only caveate is to be aware of the root mass when you are riding it down. I occasionally find Maples may have a fair sized mass that magically appears under your tractor...since the tractor underbelly can be exposed.
Use the weight of the tractor and tree to your advantage, rather than trying to just apply brute force prying at the roots with the
grapple.
One last suggestion, it's significantly easier to use the full tree as leverage rather than cut down the tree, and then try to pry the stump/root out!
One of your photos looks like you are using a tow strap and maybe chain for pulling brush.
My experience is a
grapple combined with the tractor weight to push and leverage against the target is ALOT faster than getting off and on the tractor using a chain to pull out brush and trees...at least on the 15 acres I've cleared.
I had one small area that I had to do that way...and even with my wife driving the tractor and me just dedicated to chaining...it wore me out quick!