Participial constructions

[hola-olha]

help me, please, with Participial constructions:)
I don't know if these sentence actually have them, can u tell me please if they do have them.
1. The eventual launch of a Social Democratic Party, possibly with Mrs. W. as a leader, is one tactic being seriously considered.
2. Mexico City – Having long considered a strong military unnecessary, Mexico suddenly decided to spend a portion of its oil earnings on armaments – and for the first intended to buy supersonic jet fighters in the United States.
3. We will not seek to frustrate the consensus, since it is not in the world interest to have the work of the General Assembly immobilized in those troubled days.
4. The bureaucratic management remained the directors and managers of the new nationalized industries, with a few right-wing trade-union officials thrown in for luck.
5. Being remarkably fine and agreeable in their manners, Oliver thought them very nice girls indeed.
I will appreciate your help!

[Soup]

Here's the first one:

1. The eventual launch of a Social Democratic Party, possibly with Mrs. W. as a leader, is one tactic [which is] being seriously considered.

[hola-olha]

thank u very much!

[bhaisahab]

2. Mexico City – Having long considered a strong military unnecessary, Mexico suddenly decided to spend a portion of its oil earnings on armaments – firstly they intend to buy supersonic jet fighters from the United States.