As corys are shoaling fish,i recommend that a shoal of minimum of 6 are the best.Corydoras seem to be less shy and more confident and settle more quickly in their new home.Being in a shoal also bring out their natural behaviour and maybe when settled they may even spawn.
As C.brevirostris are kept in temperature between 68-75.2(20-24 celsius)farenheit,listed below are a few small plec that be kept in this temperature range.
,must be kept in group of minimum of 6.
The plec i listed are commonly available and less expensive and easy to keep.There are others in this forum who have a great knowledge of plec,they can help you out and give you advices on what plec to get.
Good luck.