1997 1.8 Na return and feed line
 

I have an oil filter sandwich plate with three ports o I can use that for my feed line, but do I have to tap my pan for a return line? Is there any simpler safer alternative?

Yes.

No.

can I get an approximate depth to drill in as to not damage the internals?

1/4-3/8 inch
Its actually kinda hard to mess up drilling a pan to be honest

Best thread you'll find for drilling the oil pan.
https://www.miataturbo.net/diy-turbo...e-story-89997/

Basically when it breaks through stop, the tap can work out the rest.

Or my sarcasm can kick in and tell you that 60psi on your return line will totally work, and you should try it for science.

since chicks do dig miatas I will praise you, but I am a noob as far as turbo methodology so thanks for the pro tips guys!

find the flyin miata turbo kit installation guide and follow it.
fairly simple process and the rest of the instructions will show everything you need to know how to bolt on turbo and all supporting bits.