I bought my hub tool at NAPA for $24 and ground down the knubs so they'll fit the VX (it was for some other truck). However it really wasn't needed. Once the 3 screws are removed the retaining ring taps out as already mentioned - there's hardly any real torque on it. Buy a set of screws for each side in case you strip out any of the heads (common) but if you use a new screw tip/driver that's the right size you shouldn't have any problem.
To make things easier, you can get a bearing repacking kit - it's a double white cone that the bearing fits between - top cone fits the threads on a grease gun - I used that green grease that's rated for water submersion on trailers but anything rated higher than the manual will work fine. While the bearings are out check for any scoring. I found the kit at Harbor Freight for around $5 but I've seen it at Discount Auto Parts for around $9.
I found a new in box EGR on eBay for $90 (shipped from Puerto Rico from a closed Isuzu dealership) and as you said, it's a GM replacement part and works fine.
How about finding some used tires local to you to replace the two that are worn, just to pass inspection? It could buy you some time until you do the lift.
-- John