Does Defect Filing case means Filing within Limitation?

Yes, defects may be cured later on and after curing the defect, case is considered being filed within limitation.

Initial date of filing shall be considered for counting limitation, even if there are defects/ objections.

Why so many "IF...." "IF ..."  which implies that it is a hypothetical and fabricated time pass query, isn't it?

First of all, a suit that is barred by limitation shall be dismissed in the initial stage itself if there is no proper explanation for the delay in filing the suit beyond the limitation. A few genuine examples are:

1. If there were sudden holidays of the Court which were otherwise not declared holidays like imposing of a curfew or natural calamity etc force majeure
2. If the Defendant was out of the country fact of which needs to be properly proved with documentary evidence