If after doing wudu, I have a shower thoroughly, with soap/shampoo, will it be considered ghusl?
There are different obligatory requirements of ghusl according to the various schools:
- having the intention to do ghusl
- pouring water over the every part of the body
- rubbing every part of the body
- rinsing the mouth and nostrils
Using soap or shampoo does not play a part. As long as you have done the above actions your ghusl should be valid.
For further reference see: Islamic Jurisprudence According To The Four Sunni Schools