2 is sufficient to grow even high demanding plants in a 70+ gallon tank with the light 4in above it, of course with proper plant and tank maintenance. I'd keep another one in stock, just in case.
Those plants will work out, however don't expect the AR Mini, Ludwigia SR, AR Lilacina, AR rosefolia, and ammania nesaea to be fully vivid in color. They will do well, just not at its full 100% potential.
The heternanthera zosterifolia will need more care if you want it to be lush and bushy.
The Lobelia Cardinalis will also need more special care at the bottom part of the plant. Trim the tops of it accordingly to get the most out of it.
The rest of the plants will do just fine. I'm not sure about the Blyxa Japonica, because I haven't had any experience with that plant.
For the lights, umm 8 hours day....hmm maybe you'll have to replace them after 5 years. I'm not quite sure, but I would save up for an led light if you're planning to do a heavily planted aquascape. If not, I think you can get away with it and just replace the lights when they fade out or do strange things.
"Adopt the pace of nature: her secret is patience"