It's a G16 engine - which G16 can probably be determined by checking the engine number - it will say G16x-nnnnnnn - where x is a letter (usually A or
and n are numbers (the actual engine serial number).
Now - I have good news & bad news for you - first, the bad news - unless you can determine exactly what vehicle that engine was removed from, and exactly what was done in the conversion, the quest for acquiring information (like a wiring diagram) and certain parts is going to be VERY challenging.
The majority of Escudos are used JDM (Japanese Domestic Market) exports, the documentation (where available) will be in Japanese, certain parts, especially in the fuel injection and emissions control will be unique to the JDM market (that is assuming the ECU, etc., from the Escudo was used in the conversion), other parts will be common, but, the only way to find out what fits, will be to buy it & try it.
The good news? Things like the "rear back seal" whatever that is, are probably interchangeable.
With regard the radiator - I think your best option is to find a local radiator specialist and have them fabricate something for you - the option that you have in mind will require you to identify what's fitted (is it Samurai? is it Escudo? is it something else altogether?), because there's nothing that says it even has to be Suzuki part - I've seen Civic radiators used on those conversions.
I'm sorry to be the bearer of bad news, but, I see no point in "sugar-coating" things - maintaining a JDM vehicle has it's challenges, maintaining someone else's "frankenstien" creation has it's challenges, add the two together, and.. well.. expect challenges.
One last thing - be patient - there's less than half a day between your first post and your second, most of the folks here have jobs, some are retired and hang out here all day, but no-one's sitting here just waiting around.