Not OP but I am in the process of upgrading my M93P Lenovo Thinkcenter. Uses laptop ram and simple to replace hard drive and RAM. I am far from a hardware guy.
Yes to both
2x DDR4 SO-DIMM RAM (notebook) slots. No ECC though (at least on this model)
And you can have 2 storage drives. One 2.5" and one M2.NVME