If you want visible oil temp/pressure or coolant temps then you'll need to either fit an aftermarket guage or something like Scanguage to read those figures as the FRS doesn't have them as standard.

Regarding keys the FRS should have been supplied (new) with 2 Ford 3 button keys that operate the Ford locks (lock, unlock & bootlid open), 2 "RS" badged fobs which operate the Cat1 alarm fitted to the car, and also 1 generic key which has the key number for cutting purposes.

The "RS" Cat1 fobs can still be sourced on ebay & Ford but to get them coded to your car you'll need to get them coded by a dealer

In relation to books, the Mk1 FRS came with exactly the same books as the standard Focus as the majority of the car is the same - the only additional booklet was one labelled specifically as "Focus RS" which covered the specific RS parts like the dash, starter button, etc

The car should also have a set of "RS" logo tailored mats.

By all accounts though it sounds as the last owner(s) of the car have sold the car on & probably kept all the "RS" specific items and sold them on ebay (as is normally the case with these cars)

In any case if you can have a look on the RSOC forum as all the info/answers are within their Mk1 section of the forum