New with questions on LinuxCNC and Mesa

I am new to the hobby CNC game. I currently have a little 3018that runs GRBL I bought to get my feet wet. My day job is CNC electronics maintenance so I have some experience with industrial controllers. What I would like to do is get a machine running with dual feedback. The biggest issue I have with the little guy is step loss. From what I have found you can run "closed loop" stepper systems which sort of solve the problem but not really so I want to build a system that will do exactly what I want and I was told LinuxCNC and a Mesa controller is the way to go. I have looked at the Mesa site and am thoroughly confused on the options. I see that I'm probably going to want an ethernet connection for real time. I'll have Linux running on a stand alone laptop so I want the controller external. I also know I'll need drivers for the servos and power supplies. Which controller and which daughter boards I need are the problem. I will build a 3 axis gantry machine with a slaved pair of Y motors. I would like future expandability options for a 4th axis down the road. I want all 3 axis to run rotary feedback on the motors as well as linear scales for each axis with machine primary positioning done from the scales and compared to the encoders. This is how industrial CNC machines run. Is this something that LinuxCNC and Mesa control boards can handle? If so can anyone help me out with selecting the mesa boards I would need to accomplish this?

Typically, unless you need linear encoder feedback, you can use servo/closed loop drives that
just have local feedback, (no feedback to LinuxCNC) so you don't need encoder inputs, other than
one for the spindle if you want to do spindle synchronized moves.

For a simple system, I would consider a 7I96S or 7I76EU (the main difference is the the 7I76EU has
more digital I/0.) If you are sure you want to add encoder feedback a 7I95T would make more sense,
though you can add an encoder daughtercard to a 7I96S or 7I76EU (7I85/7I89 = 4/8 added encoders)

Thanks for the info.

So the servo motors I'm looking at are integrated servo/driver/encoder and use stepper control signals. I'm under the impression that I would use a 7I95T card. Seeing as Y will have a slaved servo I'll be short one feedback channel. So I would get a 7I76 to plug in to the 7I95T correct? Then I will have all 7 feedback channels for the 4 servos and the 3 scales. It would also allow for future expansion of an A axis with feedback.

Now, If I go to run a spindle with encoder will that be handled by the 7I95T in addition to the 6 axis channels it has? Also, is this the only card I will need? It sounds like it runs ethernet to the PC and that is it.

In general there is no real advantage to have the local rotary feedback
returned to LinuxCNC (and some electrical disadvantages) So a 7I95T
would have sufficient Encoder channels.

You might also want to consider servo drives from Delta, Rexroth, or others that support direct connection of the linear encoders to the servo drive for full closed loop operation.  This is combination with absolute encoders on the servos is how I think most new machines are doing it...at least the ones I have seen.   They could be controlled from either Mesa or with Ethercat.