Having done a lot of research, there are generally only a couple of differences. Excluding the DPMS Gen II rifles. To understand the confusion, you have to look at the history and particularly the years. At the beginning, there was the ArmaLite AR-10, circa mid 1950's. But because it was not adopted by the US Military and foreign sales dropped off, there was no commercial semi-auto variant. IIRC, someone did come out with a semi-auto lower receiver in the 1980's that was matched up with a very small number of surplussed AR-10 parts kits to produce a semi AR-10.
In the early 1990's, Eugene Stoner joined Knight's Armament and refined the original AR-10 design. Knight's Armament designation is the SR-25.
In 1995, Eagle Arms purchased the ArmaLite name and then introduced the AR-10B. Pay attention to the year. 1995, right after the Assault Weapons Ban went into affect, 1994-2004. The new ArmaLite did not use the original AR-10 drawings, instead it was an up-scaled AR-15A2 that used AR-15 parts where possible. The new AR-10 didn't have any compatibility with the original (I haven't been able to find any compatibility, but if you have a correction, please reply and set the record straight). Because the AWB banned the production of new magazines for civilians that held more than 20 rds, ArmaLite designed the rifle to use a modified M-14 magazine. I designate this the original, massive confusion that still exists today. Stoner designed the AR-10 at ArmaLite, but we can't get that one. The original AR-10 offspring was the SR-25 from Knight's Armament. The two rifles had a visual similarity because of the slanted rear interface between the upper and lower receivers rather than the radiused curve of the AR-15.
DPMS introduced their version, the LR-308 in 2005 after the expiration of the AWB. Significantly, DPMS chose to use the original AR-10/SR-25 magazine. They radiused the upper and lower rear interface and their barrel nut is different. So now we can broadly categorize the compatibility.
1. Receivers. Use a DPMS pattern upper and lower together, or an ArmaLite pattern. They don't mix and match though I understand you can use an AR-10 upper and a DPMS lower together, there will just be a gap where the angle meets the radius.
2. Barrels, bolts and bolt carriers. You can use either pattern in either receiver, just pair them, i.e. if your BCG is a DPMS pattern, use a DPMS pattern barrel. Same for ArmaLite.
3. Use the barrel nut that fits your receiver. This is most significant when choosing your handguards.
4. I've already mentioned the magazine disparity. After the AWB expired in 2004, ArmaLite started making their own magazines and no longer converted M-14 magazines. They were already behind the market curve for non SR-25/DPMS magazines and a few years ago they introduced a receiver that used SR-25 pattern of magazine. I'm not sure of the dates, but I'm sure the introduction of the Magpul SR-25 PMAG had something to do with it. Virtually all new manufactured receivers use the SR-25 standard.
5. Oddballs. Rock River Arms developed a variation during the ban that used FN-FAL metric magazines because they were plentiful and cheap. Because of the difference in design between a magazine intended for a tilting block lockup and a rotating bolt, they had to modify the bolt, eliminating one locking lug. There were also receivers made to use HK G3 mags.
6. Small parts. DPMS put their forward assist in a different place than the SR-25 as they combined the FA with the case deflector. So while it won't stop the rifle from running, if you have an upper with an SR-25 style FA and a DPMS BCG, it will run, but the FA won't work. Big deal. I have a matched Aero Precision upper and lower. It is a DPMS pattern, but the DPMS bolt hold open doesn't work and I have to use a proprietary Aero Precision BHO.