1. Dashboard and little space aren't really two concepts I'd put together. The MFT is smaller (maybe a bit wider front to back, unless you include the trackstars/outriggers for the dashboard). Unsurprisingly a great deal of us use the basic MFT as a table saw replacement just fine. I think the biggest determinant would be what SIZE of stuff you'd like to build. If you were hauling 8x4 sheet goods in every day and building cabinets with the minimum number of cuts, then sure - Dashboard. But I can assure you as a newbie, that you're not going to be doing the minimum number of cuts - your offcut edge is probably going to be ugly. You're going to be recutting parts after many mistakes. It's not as streamlined as promo videos may show. Hence, just get a flat surface you can cut into and cut & learn. Looking back at your thread trying to decipher what you want to do, I see crazyraceguy has already said something similar many times too.
2. A track saw replaces a table saw when you have a flat surface the rail can sit on. The only time a track saw becomes a bit more unwieldy is when the stock is more narrow than the rail width. In those circumstances, if you have thicknessed boards that are of similar thickness, just tape them together with blue tape and shuffle them about as you joint an edge on each. Again, all you need is a flat cutting surface and your rails.
3. The main thing Dashboard provides is cutting onto the same line on the cutting surface. Some of us get very stingy with a consumable and do a lot of things to avoid making the MFT tops look like the surface of Mars. There's no functional reason, only aesthetics - and I say this as one who's avoided cutting into tops other than one rail line too. MFT also does this to some extent, with stops for repeat positioning of the rail lift. It's sloppy though, and isn't meant to be as precise as Dashboard's. But then again, you're expected to cut into the rest of the table top a lot.
3a. For small hand tool work, you really can just slap a MDF board (of any size, can be narrow, can be MFT sized) and just drill some 20mm holes into it. They don't even have to be grid. The MFT spacing is just a good standard to use to have access to clamps that can reach the entire board. I personally have a long 1.5'x4' - X2 MFT slab that I just throw onto a Dewalt Heavy Duty stand to do a lot of work in confined spaces. As long as I'm dealing with relatively narrow boards, there's no more that's needed.
