Valid concerns Allstar... I'm just viewing that challenge as part of the fun trying to do this. As long I get a reasonably in tune, reasonably in time dry vocal track I should be good.
I'm using Cubase as my DAW so I'll be able to move the phrasing about a little to line all the various takes up. I'll be able to do a touch of pitch correction if that's need too. As well as all the generally EQ'ing compressing etc it'll need.
My voice will probably still be the main focus, so that'll also help keep it tighter.
If nothing else it'll be a fun experiment for me :)