Yes really snug fit just run tubing under hot water to soften/relax before trying to fit on barbs hose clamps not necessary but always recommended clamps if running higher pressures (above 12 psi).

Yes it will work if you heat up the tubing

It's used on gas line and not recommend it for beer as it would restrict flow and could cause foaming issues. Just wondering why would you want to split a beer line to two taps from the same beer? Hope this helps you.

Most beer lines have a bit of give so yes I think this will work just clamp it as you would any other line.