When asked to vote for delegates to the secession convention, most of the Alabama counties which provided heavy support for the Bell-Everett ticket voted for "straight-out" candidates. In other words, immediate secessionists. There's a relationship, because secession really was on the ballot in that election.
We discussed the low vote for the Constitutional Union Party in Alabama's Winston County, the state's celebrated citadel of Unionism. As you noted, Bell-Everett received a grand total of forty votes from Winston County citizens. That alone should demonstrate that there is no relationship between voting for the Constitutional Union ticket and being against secession. Most of the hard-core Unionists in Winston County must have voted for Democrats, either Breckinridge or Douglas.
Let's look at the other so-called "Avalanche" counties where the Democrats routinely defeated Whigs by overwhelming margins. All are located in the northern third of the state, stretching from the Georgia border to the Mississippi line. In each county the Bell-Everett ticket in 1860 received about the same percentage of the total vote as Millard Filmore got in 1856. No matter what the new party label happened to be, voters recognized the candidates as being Whigs and voted accordingly.
The real action took place within the Democratic Party, which split over slavery. A vote for Breckinridge-Lane could be interpreted by the public as a vote for the expansion of slavery. Democrats excoriated Senator Douglas for his position on slavery in the territories, which Southerners called "Squatter Sovereignty". In their view, Douglas undermined the rights of citizens of any states to bring thier slaves into the territories. Breckinridge upheld that right, so his wing of the Democratic Party was known as Southern Rights Democrats. The Douglas wing was called the National Democratic Party.
As noted, Bell-Everett votes are painfully small but match historical pattern. Breckinridge carried all of these counties, but Douglas ran a strong second in many of them, including Winston. These are counties where a certain element accepted the "national" position on slavery, which was that residents of a U.S. territory could vote to exclude slavery prior to statehood. Based on Winston County, we are much more likely to find unconditional Unionists (like their hero, Andrew Jackson) in these counties.
You'll have to scroll down - for some reason my tables insert a number of empty rows before you actually see the table.
|Blount County||Total||%||Former Whigs||Democratic Party|
|1860||1,251||05||65 Bell||698 Breckinridge||488 Douglas|
|1856||807||05||37 Filmore||770 Buchanan|
|Calhoun County||Total||%||Former Whigs||Democratic Party|
|1860||2,765||13||364 Bell||2,347 Breckinridge||54 Douglas|
|1856||2,573||17||443 Filmore||2,130 Buchanan|
|Cherokee County||Total||%||Former Whigs||Democratic Party|
|1860||2,466||21||527 Bell||1,706 Breckinridge||223 Douglas|
|1856||1,992||23||455 Filmore||1,537 Buchanan|
|DeKalb County||Total||%||Former Whigs||Democratic Party|
|1860||1,255||16||204 Bell||849 Breckinridge||202 Douglas|
|1856||1,030||14||130 Filmore||900 Buchanan|
|Fayette County||Total||%||Former Whigs||Democratic Party|
|1860||1,695||21||359 Bell||1,299 Breckinridge||37 Douglas|
|1856||1,239||35||440 Filmore||799 Buchanan|
|Jackson County||Total||%||Former Whigs||Democratic Party|
|1860||2,455||05||130 Bell||1,760 Breckinridge||565 Douglas|
|1856||1,887||05||97 Filmore||1,790 Buchanan|
|Jefferson County||Total||%||Former Whigs||Democratic Party|
|1860||1,153||21||245 Bell||831 Breckinridge||77 Douglas|
|1856||893||22||196 Filmore||697 Buchanan|
|Marion County||Total||%||Former Whigs||Democratic Party|
|1860||1,245||16||197 Bell||986 Breckinridge||62 Douglas|
|1856||898||22||198 Filmore||700 Buchanan|
|Marshall County||Total||%||Former Whigs||Democratic Party|
|1860||1,369||12||165 Bell||441 Breckinridge||763 Douglas|
|1856||972||09||89 Filmore||883 Buchanan|
|Randolph County||Total||%||Former Whigs||Democratic Party|
|1860||2,644||21||567 Bell||1,734 Breckinridge||343 Douglas|
|1856||2,143||32||683 Filmore||1,460 Buchanan|
|St. Clair County||Total||%||Former Whigs||Democratic Party|
|1860||1,377||12||174 Bell||963 Breckinridge||240 Douglas|
|1856||901||09||83 Filmore||818 Buchanan|
|Walker County||Total||%||Former Whigs||Democratic Party|
|1860||852||12||103 Bell||446 Breckinridge||303 Douglas|
|1856||595||24||146 Filmore||449 Buchanan|
|Winston County||Total||%||Former Whigs||Democratic Party|
|1860||390||10||40 Bell||203 Breckinridge||147 Douglas|
|1856||235||06||14 Filmore||221 Buchanan|