If the LFS cycled those rocks with ammonia, you are good to go with the clowns. Right now all the people out there talking about your "numbers" are looking a few months down the road when you decide you want coral. 2 Clownfish are a very small bio-load for that much rock. even if it WASN'T cycled, if you pay attention to your ammonia levels and change water appropriately they will be fine. You are going to need at least a few more days or so before you start noticing nitrates come up. Your NH3, NO2/NO3 levels are right on with what i would expect to see from store cycled rock though. You won't see any ammonia or nitrite, the rock(bacteria in the rock) will convert all of that to nitrate quicker than it can accumulate in any measurable fashion.
For what i would do going forward:
Keep the clowns
Measure ammonia daily - if it climbs above .5 do a 50% water change
measure nitrate either daily or every other day - if you see it going up with no ammonia build up your tank is "cycled" and you can start adding more fish SLOWLY, let the tank grow to match the load.
Don't even measure anything else other than salinity this month, none of that is going to change enough to matter.
i would NOT do a water change until nitrates hit 10ish ppm, then do a 10-20%, nitrates below that are your friend and you want that, but NEVER 0. In about a month, maybe 2, when you start to see algea, watch your phosphate levels too. may seem counter intuitive, but make sure you keep them up, like between .05-.1 ish. In a new tank they will want to stay at 0, that is when you hit some nasty stuff vs green algea that is ugly but useful and easy to deal with. At about 2 months in, you will probably start seeing the "uglies" they will run their course. Dont do anything drastic, stay the course and get more clean up crew. After 4ish months if it has calmed down and you have the hang of keeping things stabile, start watching your alk/cal/mag/ph levels. if those are good and stabile it is time for coral.
You can speed this up, but if you don't know what to watch for it can go south VERY quickly and you will end up killing a lot of coral and maybe some fish. That is why most people recommend to take it slow. It is so easy to see all this beautiful life and want to jump in, but this is a game of patience. Stuff happens on the scale of weeks/months, not hours/days. (unless it is bad stuff. that can happen in minutes)
Good Luck!