Table height depends on you, it will be what you are comfortable with. I went cheap, it is a hobby, I made a ball vise using a bowling ball. I cut the bowling ball in 2 pieces, one I mounted a drill press vise, the other I have a stub of a 1-8 threaded bolt sticking out of it. The latter I can mount the chucks from my wood lathe. The latter is my woodcarving vise, but also gets engraving use. Lots of pictures on Google images of bowling ball engraving vise.
For magnification, I went with the Optivisor. At $25, it was cheap, and I also added a couple extra lenses, once I found the lens that worked best for me I bought another headset just for it. Total invested is about $65 for 2 headsets and extra lens.
Sharpening, I looked at the Lindsey templates, the GRS systems, then I got to studying them and finally followed Shaun Hughes video on making a sharpening template. This video. Made some changes, first I took apart a T handle tapping wrench and used the collet end as my tool holder. Using a protractor, and flying by the seat of my pants, I came up with the angles that worked for me. I went with 1/8" square and round lathe tool bits that I got from MSC for my gravers. I also spent hours searching the Internet for ideas, and have some other sharpening "concoctions".
I had tried the NGraver handpiece that is powered by a Foredom unit. It was my only major engraving purchase, I found a complete used unit for $220. I also chose it because of it's woodcarving capabilities. Foredom also has a similar unit on the market, I think it is less than $400 new. But I also used Maze concrete nails to make hand gravers, the nails were cheap, they were my experimental source for designing my sharpening system.