I once built a complete starter kit: forge, blower, anvil, basic tools for under US$25; if that's too expensive perhaps this is not the hobby for you; oh I see "stores"; so you are trying to buy stuff at the most expensive places and wondering at the cost. Flea markets, yard sales, barn sales and scrapyards are where I find tools. (Found a lovely set of Diamond Farrier tongs for $5 today at a flea market down here---wasn't there yesterday when I checked then. Learn how to re-handle hammers properly and the handleless heads go for cheap. (and many old tools will need a new handle anyway, why pay extra for something you have to throw away?) Learn how to judge a good handle before you buy it too. The biggest problem I see is you are wanting to start backwards "I want to start with my doctorate and then branch out to a masters and bachelor's degree" Bladesmithing profits HUGELY from knowing how to heat and hit metal learning the basics first speeds up the process immensely. I have a lot of students who want to dive into bladesmithing before they have decent hammer or heat control. I will often allow them to do a blade early on and then when they mention that they have spent 12 hours filing it to get rid of the hammer marks and now it's too thin to make a blade they are willing to go back to learning the basics. As I tell them: everything we do making a simple S hook applies to making a knife; so try to get good at that and then we will add on the next step. It's a lot less frustrating making a series of simple projects that you can give away or sell than to make a pile of scrap steel worth pennies per pound
my wife chose the color of our new metal roof to match the colour on my shop building which matches my tool color (and was all free metal for the shop due to a massive hail storm causing every roof in the nearby town to get replaced) Good job to get your son involved; hammering nails is a great way to practice for hammering hot metal!
How would you expect to weld something 4' long without parts of it not dropping under welding temp as you worked? Viking pattern welded blades were made in a fairly normal sized forge. Japanese one too. Do you have years of experience and want to do something out of the normal? If so we can help; otherwise this sounds rather crazy. (and the way you increase the length of a gas forge is to essentially build two or more and hook them together---more burners, longer tube.)
Ball bearing test would be mandatory; how badly do you need it? $1 to $2 a pound is *MY* range for anvils but I have enough to work on and so tend to lowball prices for other anvils so I can pass them on the students. If you don't have an anvil and that ones passes the test I would think that US$200 would not be a terrible price. I would not go top dollar as it is damaged and worn. If I had to do a pre 1820 impression I might go up a bit more as it would fit it and be a sizable anvil for that period! (you sure 164#?)
Some very nice ones in "Iron and Brass Implements of the English House" But yes it is allowable to make it a lift off version. As most of them were made with real wrought iron I don't recall anybody trying to avoid welds and some of the ornate ones had a veritable plethora of them. Of course I have not seen very many "modern" ones as compared to several hundred historic ones so the change in materials in the late 1800's very well could change the way they tended to be made. (Does the foxfire books have an example? my copy is about 200 miles north right now.) How will you fasten in the pintles? that may have a bearing on what they are put into.
If you are going civilian then you need to look at that time period in general; don't forget that thousands of blacksmiths worked in factories back then and VERY FEW WORKED PORTABLE SETUPS. You need to decide what type of smith you want to be as a starter and what type of shop.
I took an "out of hours" brass casting course at a local University with a friend and he cast a brass hammer for removing pegs from Japanese sword tangs. We used petrobond oil sand for the mold and he took his toddler son's little wooden hammer from a peg pounding toy for the positive. Didn't make a match plate. Rammed it up in one /12 the flask then cut to the parting line, used parting powder and rammed up the second half of the flask. To make it more interesting he took a bunch of leatherworking stamps and tooled the sides of the mold save for the hammer faces ended up with a very ornate small brass hammer. (the instructor, who was an artist and expected people to do small jewelry pieces, put a limit on the size of the pours the next time he gave the class)
Back about 30 years ago I used to take some sq cut masonry nails and ground rounded ends on them to use to "push" guard metal towards the tang and then also peened the face of the guard to hide the evidence/make it more showy. (actually if you do it carefully and all around the tang then it can look like an intentional ornamental inset)
ASM Metals Handbook, (for my version Heat Treating is Volume 2). My got to place for information on how to handle a new alloy and how I learned that S1 does not profit from normalization before hardening...However as the charts and instructions are generally worked out for a 1" sq cross section I have to work out how to treat knife blade sections from there.