Never been to the Lemp myself but I've done enough investigations over the years to know that basement reports from that place are consistent as hell. Cold spots, pressure in the chest, that heavy feeling like something's watching you from a corner. I had almost identical sensations in a building out here in Roswell back in 2019, completely different context but same physical response.
What time of night were you down there? In my experience the middle hours between about 1 and 3am seem to produce the strongest reactions in locations with a lot of residual history, and the Lemp family left behind a mountain of that.
Anyone else been recently? Would be good to cross reference what people are picking up.