TvZ Question

Low level Terran here with a question about scouting Zerg.

Sometimes I get my SCV or reaper in and see that a spawning pool is present before a second hatchery goes down in the natural … am I correct in assuming that this means a zergling rush is incoming ?

Same scenario but this time Zerg has 1 or 2 gas and a spawning pool before second hatchery …. What changes in this situation?

Same scenario but sometimes I see that queens are out early … am I correct in assuming that Zerg is likely forgoing early pressure for more of an economic build style ?

Any wisdom shared will be greatly appreciated ! Thanks