need pond setup advice

Hello all. I am hoping you might be kind enough to give me a little
advice. I just dug a 19'x10'x2.5' hole that I would like to turn into a
pond to house common goldfish and aquatic plants. I have a pond that
was built by someone else and is basically a liner, pump, and hose to
the top of a waterfall. My existing pond seems to maintain good health
and requires a drain and clean aprox. once a year to remove built up
muck. I am interested in how effective a skimmer is in eliminating an
annual drain and clean and if Firestone epdm roof liner (I can buy Pond
Guard liner on line for about $.50 a foot with shipping and the roof
liner for $.37 per including tax locally, Pond guard $.95+9% per
locally) can be used. I was also told roofing felt was a good
underlayment. I would like to save where I can, but also not skimp on
quality if the difference in cost is close. So I guess my questions
are;

1. What type of liner 45mil or 60mil, roof or pond epdm? Roofing felt?

2. Filter such as skimmer effective and or necessary?

3. Pump brand recomendations ( pond is 2500 to 3000 gal. with a 20 ft.
run to a 3 ft. tall waterfall)?

4. Does any one know of a reasonably priced supplier in the New Orleans
area? I've tried the usual suspects and liner is is 100% higher, pumps
50% higher than the internet.

Thanks in advance