for your 4th axis you'll need the driver so that alone will cost a good chunk of change so would it be worth it in the long term to create an abortion that won't match up to your haas control if you ever plan to run the machine like its meant to or is it worth spending the extra to have it all proper
with the probing is it an i need it or an i want it thing , probing can save some energy for edge finding but not much , and a sweep with a quality dial will usually produce better measuring results .
automatic tool probing is only worth having in high volume production machining cells that run multiple pallets where tool breakage may be an issue , otherwise it takes seconds to manually qualify a tool
I can understand the macro need or want ,
I'm not trying to neg the idea , i simply look at it as you've spent the money to buy yourself a nice little machine setup and some things are worth waiting for the time when the money is there
converting it to run from mach would be a step backward i think,
A poet knows no boundary yet he is bound to the boundaries of ones own mind !! ........