The 32 "basic" calculators are normal stuff you do with a pocket calculator, engine displacement, CFM flow, head gasket thk compression change, etc.
QuarterJr/Pro is an easy way of keeping track of your passes and analyzing them and doing "what if's".
The EngineJr/Pro is probably not going to be of great help since it's gasoline based. But who knows?
Yes, there are calculators like these online for free, but most require you to be on the internet to use them.