I had many questions, but you seem to be well underway. I have dug many ponds with great success. I was going to ask type of soil, location, room to move spoils, and depth. 4-5' deep is a bit on the shallow side especially when it comes to cattails and weeds in general. Bad soil (quick drainage) can also break the bank. Most pros will do a test dig 1st just to see what they're dealing with, if it's clay great if it's sand not so great. If you are going to stay shallow then one suggestion may be to line the sides with lime, there are companies that have trucks just for this application. There are all different types of ways to line the pond, pretty much depends on what your price range is and what is avaible. Put an add in the paper(craigslist) and see if anyone close by has clay. Sometimes you'll find clay for free, you'll just have to figure trucking. Don't forget a lined pond could have an issue when it comes time for cleanup/dredging(that would be down the road so not a major deal now). Also if you line your pond make sure you dig deep enough to allow for the extra clay or........ what ever you use.
As far as digging it yourself don't be discouraged about the nay sayers(they're just jealous ), if you enjoy it then have at it, after all it's your time and equipment. Just keep in mind there is more to a pond then just a hole in the ground, as you are learning. My hat is off to you or anyone else willing to atleast give it a try, in the end you'll have learned something and hopefully have successful stories to brag about
I would think a dozier/dozer? could whip out the pond and roll the berm with in about 6 hrs.
Less wear and tear on the tractor and someone that may have done the same job before, and may know what you need in additions, like clay, lime, or liner..
Perhaps you might want to dig with BH on bottom of pond as deep it will go to see what type of soil there is down there. Also dig somewhere else on the property where there might be clay in a poor draining area or poor growing soil conditions. Finding your own source of clay is your best bet/solution at this point to line your pond with. :thumbsup:
For liner material, I would recommend you look into Bend Tarp and Liner BTL pit and pond liners direct from the leading manufacturer This is a commercial grade material used for industrial applications and is priced below what consumer grade liners sell for.
I forgot to add you should try to go for a 3 to 1 slope, for every 3' out drop a foot. The only place I'd have a drop off would be at the edge to help control weeds.