Kinda late now... but both Motorvation and DMG sell clamp-on clevis type fittings to bolt to the frame that eliminate welds - at least where you have an existing frame member.
This clevis pin type locks the joint into one plain of motion only (usually vertical, but it swivels if you need to adapt), and eliminates the full 360 degree possible failure mode on the stock DMC/Ural hardware - that's why the ball/socket stuff is usually replaced. While bolt on, they clamp to the frame very securely; we have yet to have one fail, although I do re-tighten annually or so.
Your heat shield turned out great. The steering damper may indeed be required; unless you want to go the VW route (google "sidecar VW steering damper"), I have used the Motorvation version with success. Larger, heavier duty, and they sell it with clamps to fit your fork sliders. I would consider a fork brace mandatory, as the XS forks are rather wimpy to begin.
Nice hoop bend on that rear lower mount. Hard to hang something where there ain't no steel... On the HD, I ended up effectively extending the lower frame rail back to this area, using a 2"wide x 1/2" thick piece of steel - took me days to fab this thing, and then weld bosses onto the frame to bolt the fab piece to.
Your hoop does stick out there a lot, with point loading at the end; this thing will want to bend. You could prolly get by with welding an external 2 piece sleeve onto the XS frame (to reinforce and spread the hoop loads), then bending and welding some 4130 (chrome moly) larger (1"?) diameter tubing (min 0.12:, maybe even 0.15: or 0.18; wall) to duplicate your hoop; that should resist bending and shock loading - I think; depends on how hard you ride, and if you are wont to hit curbs and stuff... If you are going to pile up the miles, maybe call Motorvation or DMG and see what they have to offer? They have been doing this awhile, and have decades of "oh sh!t" experiences... it would be recommended to heed their advice.
While my recommendations may seem overkill (like 0.1875" wall), there are incredible forces exerted on the bike frame by a hack; it is an un-natural pairing. Again, a metal/weld failure at speed may be the last thing you get to experience...
Legal Disclaimer... I am no expert, and you would be a fool to rely upon my comments as anything other than the ramblings of a idiot.