dart 1969 beginner questions

Hi,

I recently fall in love with the dodge dart model. I saw a 1969 slant6 and want to buy it and change the engine for a 318 and I have few questions before starting this project.

1. Does the 318 parts are easily available. I know that this engine is common in the 1990's dodge pick-up but is the parts can retrofit in the 69 dart. And same question for the slant6 225 if I stay with this engine.

2. Does the automatic transmission for the 318 is a 727 model and is it a column or floor mount shifter.

3. Does the like that we need to change with years like brake pads/drum/disc, shocks, rad, gas tank, hub bearing, ball joint are easy to find for this car.

4. Is the service manual for A body mopar is availailable to download somewhere in this forum and does it have a DIY section.

Thank you very much