The answer is no, they can’t roll together.
^Exokek wrote this when I searched for the topic.
Here's something I put together a while ago while I was ISOing a near impossible wand. It might help you understand a bit:
https://forums.d2jsp.org/topic.php?t=92289849Items have a base "tier" they roll from based on their own iLvl.
Then, staffmods can spawn either at that tier, below that tier (-1 or -2), or above that tier (+1)
Say I have an iLvl 19-24 Bone Wand that naturally rolls T3 mods (Skele Mage, Clay Golem, etc.)
That wand could spawn with 3 different skills, but the highest it could roll is a T4 skill (Bone Spear, Blood Golem, Poison Explosion, etc.)
You literally CANNOT have a T5 Wand that rolls up +1 and hits a T6 skill like Bone Spirit AND also rolls -4 to hit T1 Teeth.
I didn't think it was possible till I used goo.gle and saw this guy had in his necro gears he was selling: