200 x 200 is a bit overkill why this size.? 200 x 100 would work just as well and save weight and money, also easier to epoxy.
Twin rails on the long axis are not needed for a machine this size and usage. Again drop them and save the money.

Regards saving epoxy then just create a strip for the rails by fastening thin lengths of 10x6 steel on the surface and use these as dams.

With the 130Kg and could closed-loop steppers move it then yes easily if you use 230V mains drives. Regards the speeds then you are making the classic mistake by thinking you don't need to move fast. To be honest it's got nothing to do with what "YOU" want to cut at and everything to do with what speeds n feeds the material and tool require to be cut at.
Get this wrong and you'll have poor finishes and wear out tools or worse broken tools.

You need to seriously work on the Z-axis. What you have now, factoring in the rails not being correct, would be very weak. There would be no point building the base frame and gantry so strong only to fit a weak Z-axis.
The Z-axis is THE single most important area of a machine because it holds the spindle. Your's needs a lot of work and seriously strengthing. I would consider moving the top rail from the front face to the top face to give more spacing between the rails and support the Z rear plate more.