old fuel lines and brake lines -Replacement Where and How? Tech tips please!

I helped a guy that used to be my friend build/resto-mod a derelict satellite I owned.

On a strict budget we blew brake fluid, paint thinner, Oshpo rust inhibitor, and rubbing alcohol through the lines and blew them out with pressurized air. Once acetone came out clear without brown rust, he used them on a mild 360 with no problems (car came with 318).

I was jacking up my car (76? Dodge Aspen) yesterday and finally saw where the routed the lines (much more difficult than my 73 road runner).

I need to get these done without placing the lines near the e-brake cable, or interfering with anything else. I would love some suggestions.

I built my own brake line on my road runner decades ago when the autoparts store had multi-sized brake line pieces in a bin. They don't seem to have that now. Oreilly's near me has nickel copper lines, but is that good enough?

Do i have to get tubing flare kit or can I order/go-drive-and-buy the same lines again somewhere?

My chevy buddy is all about a hose (not rubber i am sure, but I don't know the material) for his firebird- that stuff is cheap -but how to you end the hose line without getting leaks? I was considering that material for a fuel return line. Evidently, even buying it braided is not hard. It has been a few deployments since i looked at fuel hoses. I thought they were vulnerable to ethanol. Is that true?

Please give me advice for fuel lines and brake lines. THANK YOU!!