@Adam S.
Thanks for the feedback, negative though it may be. Can you elaborate on why you would never do a tax sale again, even though you were successful?
You're the first person I've seen to suggest that the law is untested --- the law seems pretty clear. I spoke to several lawyers (I am an attorney myself but not in Louisiana) and did a lot of reading and it seems fairly settled that once the redemption period is over, an action can be brought to quiet title and take possession. The question is whether the action will be successful because of how murky the chain of title may be. Though, supposedly, the city fixed that with the most recent sales. Who knows.
My partner and I felt that it was worth the relatively small investment to see what happens. We bought 5 certificates, 1 has already been redeemed (without us contacting the owner), and with the other 4 plus the 2015 property taxes that we paid (with regards to your suggested strategy to not pay the taxes, that seems downright silly --- why would you purposely cede the first position lien? If you've already bought the certificate, there's no point in letting it go back to the tax sale...), we've put in $3500 total. Not much split between two people.
Of the 4 remaining, 3 are houses and 1 is a vacant lot. Obviously we don't know the interior condition of the places, but looking at them for the outside they seemed better than "worthless".
#1. A duplex in St. Roch worth between $75K-125K according to various real estate sites. According to crime stats, a low crime area. It seemed as if people were living there, though it's not in the best condition, it's certainly not "worthless".
#2. A house, also in St. Roch, worth between $60-$100K, also a low crime area. Can't tell if people are living there, as there seems to be a auto body shop operating out of the garage. That one could be dicey.
#3. A 1900 sq. ft house in Central City close to the Garden District worth between $90-$150K that appears to be occupied and looks in very good condition. Can't imagine this wouldn't get redeemed.
#4. A vacant lot in a neighborhood in Hollygrove surrounded by houses worth $100K-150K according to Zillow. With the lowest crime rating on Trulia. Seemed nice to me out there, but apparently even the mention of Hollygrove is enough to scare people. This is the one most likely to not redeem, I would say.
We are still debating whether to contact the owners. It is probably a good idea, but if there's even a 5-10% chance that they don't redeem and we can get title, that's worth it given the minimal outlay we have invested. Ultimately, we thought it was worth the risk, because worst case we're out a few grand, best case, we get property worth 6 figures, and most likely case, we pick up double digit returns for almost no work.