Well said, That will show everything you need, In general bristlenoses are like the guppies of the pleco world.. they breed a lot easier than others..
THe right caves and good water quality should see some results in the future, They would be better in their own tank but should be ok in a community as long as there are no fish that could or would eat the fry, and powerful filters should have intakes covered with a sponge (like a fliter sponge adapted) to stop them being sucked in.
they like a good current but it's not 100% neccesary. I have 4 bristlenoses in my tank, they're all juveniles but growing really quickly, most likely within 3 months they'll be big enough. i researched a lot about breeding them and have not yet had the opportunity, perhaps this time they will take a liking to each other.
It's just a matter of time, unless you'rs don't 'like' each other.