As samoht said, you may use items from any EP/SP but you have to include items to allow Sims to skill up in
all the base game skills.
Since the requirements say 'base game skills', does that mean the computer has to be good enough to be used for chess as well as writing?
I left out the chess table as a requirement because Sims can use computers to skill logic. By all means, add a chess table if you wish.

And yes, remember the lot size is
30x20 and under.