Yes Tyson beat every champion and the linear champion. Douglas took that title from Tyson and lost it to Holyfield. Holyfield lost it to Bowe and Bowe fractured the titles by vacating the WBC. Noone has done what Tyson has done since.
In fairness to Lewis, he did hold the WBC, WBA, IBF & Ring titles for a short while after beating Old Holyfield in '99, but the WBA stripped him of their title before his first undisputed title defense against Grant, for not fighting their mandatory Ruiz instead.
Lewis did not unify all three titles separately. He took the IBF and WBA from Holyfield. Tyson did it in three fights, Berbick, Smith, Tucker.
Bowe ****ed up when he threw the belt in the trash and ducked Lewis as he essentially destroyed the lineage, and bar a brief moment by Lewis we have never had a truly undisputed heavyweight champion since, which is pretty sad. Now, we have two brothers holding all the belts who are never gonna fight each other. This might not have happened if Bowe hadn't dodged the Lewis fight.
Bowe did nothing that hadnt been done before. Holmes dumped the WBC and took the brand new IBF belt rather than fight, i think, Page. Lewis wasnt the concensus number one at the time, hence WBA and IBF not stripping him. He was allowed a voluntary defense, Dokes, and the nature of the first Holyfield fight dictated a rematch was always going to happen. Most at the time felt Bowe Holy was the legit title fight Lewis was stripped for not fighting Byrd and Ruiz so would still have same scenario with Klit Bros
No, Bowe was still the linear champ in my eyes. Ditching the WBC belt was little more than a publicity stunt (and apparently as soon as the cameras were off Rock immediately retrieved the belt from the trash can because even he knew he had to hand it back to them and not just leave it there!)
In terms of lineage, he would have had to formally anounce his retirment for his position to become vacant. You can't be stripped of lineage for being a classless jerk.
Bowe was more overt but Lewis did the same thing by fighting Grant instead of Ruiz, who then fought Holyfield for the WBA title and Vitali rather than Byrd, who also fought Holy for Lewis' dumped IBF title. Bowe choosing to fight Holy certainly wasnt an easy copout. He was allowed a voluntary defence (Dokes) who he blew out and took a tune up (Fergusson) before being back in with Evander within a year of their first meeting. Bowe showed a lack of class and respect the way he went about it but the Holy rematch was justified