Was Prison Break's 2nd season story unplanned?

Question

I just finished first 2 seasons of Prison Break (kindly don't spoil seasons/stories after 2nd season as I might watch them soon).

Now, when I was watching season 1, after the episode when Burrow's death sentence gets postponed, I felt they are quite deliberately trying for extending scenes/stories somehow. For example, in one episode, they tell about family backgrounds of all other inmates like C-Note, T-Bag, Abbruzi etc. which were interesting, but seemed a bit irrelevant to me because the way season started looked independent from their family backgrounds.

Still, I really enjoyed entire 1st season. But when I watched 2nd season, at many moments I felt that the story and escape could end in 1st season only, many scenes/stories in 2nd season were interesting but not very relevant. I got curious and then I found this on Wikipedia:

The first season received mostly positive reviews from critics with universal acclaim from audiences.[2] Furthermore, it performed exceptionally in the ratings and was originally planned for a 13-episode run, but was extended to include an extra nine episodes due to its popularity.

So clearly, they extended episodes in 1st season.

Honestly, I personally feel second season wasn't planned originally. I feel the director of the season had intention for their successful escape when the plane arrives in the last episode, but once they realized the season is getting popularity, they deliberately made the plane not board them and the story changes to Plan-B in second season.

And I feel all tattoo related tricks/plans in 2nd season were planned later only, as they were not as convincing as it were in 1st season.

But I would like to know if entire 2nd season wasn't originally planned (e.g. inmates family stories, Bellick's involvement in helping finding inmates, Bellick being a prisoner, love stories etc.)? And planned later after seeing success of 1st season? Is there any reference to it?

Another way to ask my question is:

Was the story of the two brothers making a successful escape from Prison and proving him not guilty in court originally planned to cover in a single season (i.e., 1st season)?

Answer 1

The show was originally envisioned to end at Season 1

While the campier later seasons offered some high-octane action there's no denying that Prison Break lost its credibility and sense of focus once the characters broke out of prison. The show never seemed sure of where it was going after the escape, but the original plan for the series would have avoided this pitfall. Before the show became a standard broadcast drama, Prison Break was written as a limited fourteen episode miniseries, which would have logically ended with the two brothers escaping Fox River.

Source

Also Wikipedia seems to confirm

Prison Break was later considered as a possible 14-part miniseries, which drew the interest of Steven Spielberg before his departure due to his involvement with War of the Worlds. Thus, the miniseries never materialized. Following the huge popularity of serialized prime time television series such as Lost and 24, Fox decided to back the production in 2004.