From the looks of your bucket you won't need to weld any more reinforcing strips! You will however need to grind off that center bucket hook. That is exactly where you will need to mount your upper jaw. Once you have a
grapple on your bucket you will find fewer uses for the bucket hooks anyway so having the outside two should be fine.
You already have a backhoe so I presume you are using power beyond to run it. If you put in a rear remote or two you'll have an easier time hooking up the BH. If you put in two rear remotes you could run the
grapple and leave the BH in place which is a very nice combo. Dig up the stumps and then turn around and
grapple'm. I had only one on my CK20 so needed to switch out the hydraulic hoses to go from BH to
grapple. A bit of a pain but not the end of the world. I would just work in an area using the BH alone and then at the end switch them out and clean up with the
grapple. On my DK I can use both together and it is certainly nice.
As you don't already have any remotes, the cost of putting in a couple of remotes plus the hoses and fittings would be roughly the same as putting in a WR Long diverter valve if I recall correctly. Maybe the remotes will be a bit less especially if you do the work yourself. If you have two rear remotes you are also in spitting distance of having a hydraulic topntilt which is a nice bonus to consider.
No doubt the electric over hydraulic is the premium package. If you plan to do a lot of
grapple work it might be worth it. I probably spend more hours with my
grapple than with any other implement but I've still been quite content with both the diverter and rear remote set ups. I always saw the budget equation as electric over hydraulic (nice) vs rear remote or diverter PLUS another implement (nicer!). So I was never inticed to go further.
You will find lots of enthusiasm for toothbars on TBN. I had one on my CK bucket but have not added one to my DK (I do have a cutting edge). I found that while the toothbar is undeniably important for digging with the FEL, that I did not use the FEL to dig much at all. I have a BH for that. The toothbar was also useful to rip up brush but once I got a taste of
grapple there was simply no comparison and I never used the toothbar again. I found the toothbar got in the way more often than it helped in other work. Nasty shin bangers too. It makes it harder to scrape up dirt from a driveway for example or to use the bucket edge to smooth out an area by back dragging. Of course you can always remove the toothbar for these tasks but that is a 15-20 minute chore and the thing is not exactly easy to store or carry around in the field. With a bucket
grapple perhaps the toothbar would be more useful in dealing with brush and the two together might be synergistic. I don't know. Maybe 3RRL or one of the other bucket
grapple enthusiasts can give you some insight there.
The other thing I would suggest you at least consider is whether to go with a true
grapple rather than the bucket
grapple. A bucket
grapple setup will cost you about $400-$600 depending on how you do it. Your bucket will still be usable as a plain bucket but you will have the jaw attached almost all the time. For around $850 plus shipping, call it $1000 to most parts of the country, you can get the same
grapple I have which is a perfect match for both the CK/DK line. That is a separate specialized implement and as with most things the specialized tools tend to have advantages over combo tools. You can get grapples with Kioti pin mounts so you don't need to add a QA adapter. If you decided to do a QA adapter though (more $$) then you open up the possibility of forks, tree booms, specialty buckets etc etc. Using just the pin mounts, it only takes about 15 minutes to make the switch over from bucket to
grapple so it is not much more work than putting on a bush hog and much less than switching out the BH.
Just some thoughts. Good luck in your deliberations.