LRDIMMs should work on your X10SRi-F.

Yes, as long as you don’t mix them with RDIMMs.

The X10SRi-F uses the C612 chipset, which officially supports both RDIMM and LRDIMM. Supermicro’s own specs for this board list LRDIMM compatibility up to 512GB at 2133/1866/1600 MT/s. So buying cheap LRDIMMs is fine if you fill all slots with LRDIMMs only. Mixing RDIMMs and LRDIMMs in the same system will not work—the memory controller can’t handle both types simultaneously.

ECC will function normally. LRDIMMs still include ECC just like RDIMMs; the difference is the load-reduction buffer, not the error correction. The board will see them as ECC memory and report errors accordingly.

One gotcha: LRDIMMs