5-year law expiry only applies to licenses. Ratings are held for a lifetime, therefore no law exam must be sat for the expired IR. (But comments above about what the examiner might ask are spot on.) Refer rule 61.37, recent flight experience.
There is only ever one initial issue IR test. However, annual competency checks are separate for TEA and non-TEA aircraft. If you haven't done a competency check in a round-dial aircraft within the past 12 months, you must do one prior to IFR flight in the said aircraft. Refer AC61_17, page 6.
A money-saving note however: approach aid endorsements are not specific to TEA or to non-TEA. Therefore, if you're current on all the approach aids you care about, you need only do the bare minimum IR renewal flight in the round-dial aircraft. You don't have to repeat all the different approaches again!