I'm a beginner too, so I'll throw my idea in there too....
I have a heavily planted 29G tank with DIY CO2 injection and about
3W/gallon lighting. Plants are thriving and algae is minimal. pH is
steady at 6.6. Fishless cycling has been completed, ammonia &
nitrites are zero and nitrates are about 10.

I am about ready to stock the tank.
1) Do I need to intoduce these type of fish into the tank when
algae is minimal - sort of for general housekeeping purposes?

you can put them in WHEN you get an algae growth spurt, otherwise you'll
have to feed them before your algae grows...

2) Any opinions on which is the better choice?

3) Any opinions on the number of either species I should keep in
the tank?

If you're planning on the German Rams, think 1 male, 3 females.... done
there... Then maybe some neon cardinals, a few tetras, or some gouramis
maybe, a powder blue, or flame red.... neon blue.... awesome colors in some
gouramis.....



Thanks in advance for your advice.

Mitch