Mukti does not necessarily always mean Moksha. it depends on how the word is used in the sentence. For example in the words like Rogamukti (freedom from disease), Rinamukti (freedom from debt) etc it does not mean Moksha at all but simply freedom or to get rid off.
Moksha is a state where soul is inactive and is considered as Mukti (Free from Karmas). But there is also Moksha in real life known as "Jeevan Mukti" (Living Moksha) Lord Krishna said, Be neutral in doing your Karma, rise above hates and loves, have neutrality for Good or Bad, Happiness and sorrow and just perform your duty with clean heart.
Which astika schools mention those muktis? These different types of muktis you have mentioned belong to the bhakti school of thought where God is considered to have a spiritual form with attributes (sakara and saguna). But because bhakti school of thought doesn't directly belong to the six philosophical schools (saddarshana), these concepts of mukti can be said to go under Vedanta astika ...
Amongst the types of mukti a mukti called sarsti(सार्ष्टि) mukti.In this Mukti it is said that you will get the opulence of god.But my question is which type of opulence does we get?
Sayujya Mukti means complete union of the soul with God, where the individual soul (jīva) loses all sense of separateness or individuality. The soul does not retain any ego or feeling of “I am Vishnu”. After attaining Sayujya Mukti, the soul is fully dissolved into the Supreme Being and experiences absolute oneness and bliss. Unlike other forms of Vaishnava liberation (like Sārūpya or ...