That should be fine for a week or two. There might be some 'interaction' between the betta and tetras thought. You might want to 'bowl' the betta for the time that the tetras are in that tank. The finage of the tetras might present the right profile to the betta to attack. BP tetras are a little nippy of flowing finage and might harrass your betta. Follow your plan, but seperate the potential combatants.
Aquascape? I'm a crypt farmer.
It's a fine line between fishing and standing on the shore looking like an idiot.
That IS an aquascape, it's titled "The Vacant Lot".