HFT vs SFT Cam Identification

OK, a parallel (sort of) question. I may need to have a cam reground. Reading the above posts suggests if the cam was originally a SFT, it could be reground for a HFT profile, yes? Or is there something else that differentiates solid from hyd cams beyond the 3-bolt solid face? As a follow up, I've read somewhere there are occasions when some mismatched lifters/cams can be used (i.e. hyd lifters on a solid cam). Is this true and, if so, what are the combos that cannot be used? Are there advantages or disadvantages to doing this? I prefer to keep same with same but would like to know for my education. Appreciate any technical help on this. Thanks.