This doesn't answer your 3 questions sufficiently,, but addresses all of them:
On Abdul Qadir al-Jilani and one of his works
Abdul Qadir al-jili, al-Jilani or al-Kilani عبد القادر الجيلي أو الجيلاني أو الكيلاني is the author of a book with a similar title called al-Ghunya li talibi tariq al-Haqq (meanings: the sufficient for those who want to seek the path of the Truth -referring to one of Allah's beautiful names-) الغنية لطالبي طريق الحق which is a book mostly printed in 3 volumes and has similarly to al-Ghazali's Ihya' four major sections (My own translation take it carefully):
- ربع العبادات the quarter of worships (which deals with knowledge and the requirements of faith.)
- ربع العادات the quarter of habits (discussing people and society.)
- ربع المهلكات the quarter (of things) that lead to destruction (in the hereafter).
- ربع المنجيات the quarter (of things) that lead to safety (in the hereafter).
The sections three and four are dedicated to the inner life of the soul and explains first the vices that people must overcome in themselves and then the virtues that they must strive to achieve.
Al-Jilani mostly starts each topic by commenting or referring to a verse of the quran then by ahadith, later by sayings of the sahaba and finally by some stories of good people.
Some editors and authors falsely considered this book as a summary of al 'Ihya because of the similar classification however al-Jilani has put more effort in quoting only sahih ahadith and disscussed much deeper and often more subjects than al-Ghazali in his work. In fact many of al-Ghazal's works have been tampered already during his life time as one can read from some of his later works.
On Ghunyat at-Talibeen
Note that in Arabic al-Ghunya at-Talibeen الـغنية الطالبين doesn't make sense grammatically as this would be a so called jumla ismiya جملة اسمية a sentence of nouns (or better a sentence starting with a noun) it is impossible that both nouns start with "al" therefore your proposed title is wrong.
It seems that the so called Ghunyat at-Talibeen غنية الطالبين is a commentary on al-Jilani's book or an Urdu translation as I found it so far only in Urdu or a colloquial title as most of us know a book called sahih al-Bukhari while the correct title is: al-Jami' ul-musnadu as-sahihu al-mukhtassar min omori rassuli Allahi salla Allahu 'alayhi wa salam wa sunatihi wa ayyamih (see for example Is Sahih al-Bukhari considered as 100% authentic by Sunni scholars?). I've not yet found out who the author is if any as it seems that the named "authors" are the translators.
Salafi's and Abdul Qadir al-Jilani
Wikipedia (at least in Arabic see here) quotes some prominent representatives of salafi school and the hanbali school of fiqh such as ibn Taymiyyah, ibn Kathir, ibn Qudamah and ibn Rajab among others whom all praised his knowledge, his asceticism, his engagement for the application of the shari'a and the fact that people loved him for his religiosity.
All this seems to indicate that salafis per se didn't have any objection to him and maybe the accusation of tampering with his books is wrong.