In my experience a few Otos or Farlowella vittata do just as good a job with algae consumption as Ancistrus and are smaller, less destructive, and produce less poop.
I've got both otos & a BN pleco juvenile, and IME the otos do a much better job on the plants, and the pleco in keeping the glass clean of GDA--esp near the substrate where it's hard for me to reach. I assume it's also cleaning up after my angels who are extremely messy eaters--as I haven't been feeding it anything, and it has already tripled in size.
"My filtration is being done through beneficial bacteria and the plants.
So are you doing a Walstad-type tank with no filter? That would probably be okay with the few small fish & shrimp you mention, but an adult BN pleco would likely produce enough waste to overload such a system. So you might want to consider adding some sort of filtration--even if it's a simple sponge or HOB filter.
If you're relying on fish waste and tap water to supply most of your fertilizer (along with your soil substrate--at least initially), you might want to consider a fertilizer supplement for trace minerals and other missing nutrients to ensure good plant growth. I'm sure many of the fertilizer experts on here can advise you on what you should use.
Completely agree that they're a very personable fish, not just an algae cleaning machine. The super reds--esp the long fins--are particularly beautiful, if somewhat pricey.
Keep us posted on how your tank progresses