First the elm device does not support(J2610 sci communication) find a tool that will talk to this computer. You need to open for visual inspection.After that you need a power supply that also has a current meter this will be your best friend repairing computers.Supply voltage I usually have mine set at 13-13.5 then make sure you are not drawing a mass amount of current if you are start feeling around all the components to see if you have one that is getting very hot this usually points at a shorted component.I use a thermal camera this works great for locating a shorted component.If you have more questions please post as many as you want thank you!!

Really not anyone I would call reliable ,Most components you are in need of are obsolete and you usually have to find a updated component to replace it with.You also can find parts from Chinese suppliers but you really should do a small test order first to make sure you are not getting counterfeit parts.

Yes on my youtube channel are videos of some of the test equipment I have built.Most all rebuilders usually build their own test equipment to their own specs needed.

Chrysler ecu are mostly the same I use the gm ls1 pins because they are cheap to buy and they fit the round pins on chrysler and most any ecu you will need to plug into to.So start with buying the ls1 terminals in bulk.Then I buy the marine shrink tube from harbor freight it has glue in it you can slide those over the term and leave them long when they harden up you have a nice long almost plastic like end to the terminal makes it easy to plug in multiple leads close to each other.

No there is not a one stop for all programming.You will need access to all diff manufacturers websites that you plan to work on.You can either pay yearly or some you can purchase daily access.

There is no one for all tool to get into that business you will need multiple tools and they are expensive.Some of the good ones are the zed full, MVP / Tcode, most of these tools you have to purchase tokens to do special functions.