query Lr using the SDK to create a list of plugins that are installed in Lr;
The SDK doesn't provide any mechanism for this, unfortunately. The only way to do it is to use SQLite to read the information from the catalog database file (which is very much unsupported by Adobe, and which can only be done while Lightroom is not running).
read a CVS file?
That can be done using the i/o facilities in Lua's base library, but you'd have to program it yourself. See lua-users wiki: Lua Csv
for an example (but note that code isn't completely correct -- it doesn't handle newlines within quoted fields).