Is This All Algae? Best Eaters?

Hi, my new (used) Rio 180 is now up and running. 

The water quality tests are spot on and the tank crystal clear except for the java moss topped mopani wood in the middle. The whole upper surface is covered with what appears to be diatoms so I get that. But there is also a grey fluffy growth mixed in with the java moss on top (nowhere else) and a creamy coloured sort of cloudy growth on the side and underside. The glass and other plants are untouched.

Do these all sound like algae or could they be anything else?

What would you recommend as a good algae eater? I have looked into a Brittlenose but I don't really want anything that big if I can help it.
I have two Otto's atm and was thinking about getting more but the two I have eat off the glass, the plants, the substrate and the filter casing but never go anywhere the mopani   
Are shrimp very effective and how many would I need? I have read that they could be affected by any plant fertilizer that I use and this is putting me off slightly.

Thanks

how come ya dont want BN plec? i have 2 think there good and something different instead of just fish lol, but you do have ottos, i have the amano shrimp and nerite snails sue suggest too