Wah Thomas,
your tank coming along very nicely. ** clap clap.
For small frag of zoas, I suggest you use glue gel.
Take the top piece of rock out, glue all the zoas frag on it. let it dry for 1 - 2 mins.
Then put the rock back inside. walah... done.
For SPS, I would only recommend montipora and radioactive.
These are quite hardy.
But still might be quite challenging in your pico.
For the sponge, once if you see it turning white, can throw away already.
corals suggestions:
get some rics and nice yumas.
Can also try getting blastos - various types of colours to choose from. can colour up your tank.
see if you can get gsp frag from somewhere.