Are there secondary causes of sea level change? Aside from the fraction of water stored as ice on land and temperature of the water, are there other factors that change sea level, and if so what are is the magnitudes of the these changes? 

For example, by how much does sediment and soluble matter entering the ocean change sea level? What about volcanoes and tectonic activity? Is there a tendency toward hydrostatic equilibrium where the Earth is entirely covered by an ocean of uniform depth?
Yes, there are lots of other factors. 

Factors affecting sea levels are no different from other natural processes: there is a large number of coupled, non-linear effects, operating on every time scale, and at every length scale, and across many orders of magnitude.

The Wikipedia page Current sea level rise lists many of the known processes. And I wrote a blog post, Scales of sea-level change, a couple of years ago with a long list, mostly drawn from Emery &amp; Aubrey (1991). Here's the table from it:



Reference
Emery, K &amp; D Aubrey (1991). Sea-Levels, Land Levels and Tide Gauges. Springer-Verlag, New York, 237p.