Ahh... would much rather have the harmonies to work with Justin. Hate admitting to using Melodyne so much for jingles though, can pretty much look at the screen and shove notes around on the fly to put harmonies together. Unfortunately, Melodyne has no {what I'd call} good auto routine to create harmonies... faster to use your ear. Mostly a third above here but there's a fifth below too in the final answer-back line at the end of chorus #2.
Time wise, this tune took about an hour to fix up the lead vocal and create the harmony. Harmony takes a little longer because a nifty trick is yanking out a little pitch modulation {vibrato} and pitch drift, in places. With pitch drift, notes usually have to be retuned = more time {I always do that manually because double clicking the note doesn't always put it at the correct interval.} Then when shoving the harmony track back in PT {or thingy of choice}, with a very slight timing offset, the harmony doesn't sound so much like a lead vocal clone.
But for this tune I corrected the original lead vocal track beginning to end as was. Then also built the harmony from that to use all the way thru. As things went, used "Ctrl M" in PT to mute the harmony in places. That way it was simple to get back any harmony piece later. But as far as Melodyne's useful range, I think if you stay in what would be considered the vocalist's natural range, it's pretty close to undetectable in a mix.
The filtered vocal was an unhappy accident and yes, probably somewhat overused. Unhappy because once it was there in the first verse, the only way in heck it wouldn't be stupid was to continue on with it. So left the first as was, second time around added the third and third time used both parts two lines in a row. Again... fly by the seat of your pants, song writing/production tricks. For PT users, the sound is the probably all too familiar "cosmonaut voice" plugin

On your part Justin, there's really nothing here that doesn't sound good. Piano was a little strident but that's surely nothing to do with the recording. I mentioned the lowend being somewhat of a battle but that's just part of the hand dealt.
As far as the mix, I really don't think there's anything special here. If there is any difference, it's mostly song first. Then trying to make it sound big with acoustic guitar/vocals as opposed to what would usually be used for "big."
No matter what, hope it was as much fun for everyone as me.