Did either of them question why Lincoln's incumbency is being threatened by her own party?  I'm guessing not.  

Was there any discussion about why it seems the anti-incumbent anger isn't confined to the other side of the aisle?  I'm guessing not.

Almost.

It may be a minor point, but the second most recent result (and the only nonpartisan result) is inadvertently reversed in Pollster.com's summary. Per Mason-Dixon, the head-to-head result against Boozman (the prohibitive GOP favorite) has Lincoln trailing 52-53 (minus 17) and Halter trailing 56-32 (minus 24).

If the candidates were Boozman and Halter, 56 percent said they would vote for Boozman, 32 percent picked Halter and 12 percent were undecided.

The notion that Halter would be a stronger candidate than Lincoln in the general election "doesn't hold true" according to the numbers, [M-D managing partner J. Brad] Coker said.

For another very minor quibble, your 'this' #1 (Rasmussen) has Lincoln trailing by 9, and Halter trailing by 19, in the same Boozman matchup.

'this' #2, incidentally, merely recaps the Mason-Dixon result, and doesn't even report matchups for Halter.

'this' #4 (Rasmussen) gives Halter marginally favorable dead duck results - minus 25, as compared to Lincoln's minus 28 in the key matchup.

And this brings us to 'this' #3 (dkos), where Lincoln places at minus 10 versus Halter's minus 5 (but with higher undecideds). This runs consistent in 3 consecutive dkos polls, where Lincoln trails by and average 10 with 6 undecided, vs Halter's average 7 with 10 undecided.

This is where the unfortunate pro's sadly out-think themselves ... raising the confusing, confounding consideration that Lincoln has been heavily "exposed" to the negative campaigning that any candidate would eventually face in a real general election race - whereas Halter is relatively untested and unscarred. (This is why an unnamed "generic" opponent almost always outperforms a named, real opponent in pre-election viability test polls.)