I have a rubbernosed pl*co in my 44 gallon tank and a pair of bristlenoses. I have many caves. The rubber nose has its territory and often chases the larger bristlenoses away from it when I feed them algae wafers. Oddly enough he has now problems sharing the wafers with my yoyo loaches, I often see them nibbling one together and also laying together. Mostly just head butts, never any bloodshed. I have several caves and my bristlenoses breed monthly.
Regarding plants, no the bristles will not eat them, they will clean the leaves if algae gets on them. I have many plants in my tank.
If you haven't had the rubbernose for very long, be warned they will sometimes lay on their back like they are dead, they aren't.
I love all 3 of these pl*cos, they are not shy and I see them all the time.