I believe milkyjoe is right with around 17k being the lowest the 3DS hit without price cut effect. ( I LOVE MilkyJoe! Isolation, isolation). But the 16k the week of the price cut is fair game too I suppose.
Vita is in BIG trouble in Japan, looking like it will go sub-10k soon. Likely to keep dropping after that. There still isn't a massive hit like monster hunter etc on the horizon. As VicViper said all we know so far is Persona 4 in June (over 3months away) and FFX at some point. Persona 4 is a port of a console game, it should sell well but not going to be a smash hit million seller. Likewise FFX is a port and that will also be available on the PS3 at the same time. So both will probably hit a few hundred thousand but they aren't going to be million sellers that massively help hardware.
Ciel no surge might do okay however the companies other similar games have only ever done a few hundred thousand at best and that has been on systems with big install bases. It should end up over 100k, but I don't think it's going to give hardware that much of a boost.
Theatrhythm is very supply constrained at the moment. Won't have the next shipment for next week either. It should have reasonable legs when new shipments come in.
Love Plus is very front loaded however at the same time the game should reach over 200k. The first game and it's updated version hit 260k and 230k. This one will do similar figures as it's just the type of fanbase.
Harvest moon opened strong. Vgchartz was saying how until kingdom hearts there were no real titles for the 3DS but that was way out. Going to be a steady stream of games hitting 100k in a couple of weeks of launch.