I'm finding that I'm really at home playing sort of slow relaxed songs especially because its the type of music I like so I was hoping if anyone knows of any or slowish songs with simple melodies. Similar to maybe Andy McKee's "Friend that I never met" or the first part of Stairway to Heaven. Even something like the second part of Ixtapa by Rodrigo y Gabriela when it starts a sort of 4 note scale sequence. Things like that.
I'm not familiar with much of what you've stated, but I've got some mellow stuff I really like to play and it's pretty easy to sing too as well....

Pink Floyd -Welcome to the Machine- translates really well to acoustic surprisingly. It's good with simple strum patters or to spice it up, I add some fingerstyle stuff where the synth solo would normally be.

Ground Control to Major Tom seems to go over well. It's on of those songs everyone knows to some degree.

Behind Blue Eye's by the Who.

I'm not sure that's the kind of stuff your looking for, but they can be learned in about 5 minutes "off the sheet" and they are all open for creative re-interpretation.
2001 Gibson USA Les Paul Studio Black/Gold
2008 Alvarez-Yairi DY40C
2004 Taylor 310
Marshall AVT275

Ex guits 2002 Ovation Elite, 1995 Seagull 12 BC Rich Gunslinger Snakeskin Various Yamaha Various Sammick Epiphone Les Paul, Epiphone ES
Here's some of the slow stuff I play. Seether - Plastic Man, Scorpions - Lady starlight, Opeth - Coil.