You can add softy corals pretty soon. Mushrooms and zoanthids are pretty bullet proof. The clam I would definately wait on, at least 3 months if not longer. You will need an Alk/CA test kit and additives for a clam as well as phytoplankton to feed it. I have always liked Crocea clams.. like the blues, purples, and greens they have in them vs the brown/white clams. Unfortunately for me, Clams are the one thing I seem to have problems keeping alive. Seems everyone has that one thing they can never get to make it.. some people it is as simple as xenias, others are sps corals (mainly acroporas), for me, and I have no idea why, it is clams.
Hold off on the Eibli at this point.. your LFS can always get another one so please don't feel like you must by that one you saw. I have been guilty of that myself several times, impulse buying of fish, and most of the time it didn't work out because I didn't do the proper research on the fish ahead of time. Not saying you shouldn't or can't have that fish, and if it is a must have for you then by all means, try one out, but at a little later time. Get something a little easier to start with, like your clowns that you want. If the clowns make it for a couple months, and no reason they shouldn't, then I would think about adding the angel at that point.
I just want to say again, the yasha is a hard fish to establish. It is a great fish and no problems with it and most other tank mates, it definately wont hurt any others, although I can't say the same in return.. but chances are a yasha would be left alone. It is just an expensive fish, and a delicate one, so take special care when selecting this particular fish. If your LFS has one and will allow you to put a deposit on it while you let it sit at the LFS for a week to make sure it lives AND eats. Never be afraid to ask your LFS to feed a fish in front of you. At the LFS where I work, hardly anyone ever asks me to do that.. just a couple people out of thousands that have bought fish, and for me, I am always happy and willing to feed a fish in front of a potential customer to show that it is healthy and eats. Last thing I want to do is sell a sick fish or one that won't eat the food the person intends on feeding it.
