Praise be to Allah (The Glorified and Exalted).
1) Allah (The Glorified and Exalted) has established a system of Formality with certain rules in relation to Himself, the King, and His lowly creatures. For example, based upon the rules of this system of formality, Allah (The Glorified and Exalted) uses the angel Jabriel (Gabriel) (peace be upon him) to deliver the revelation to the Prophets (peace be upon them). This is mentioned in the following verse, in which the formality between Allah (The Exalted) and His lowly creation is alluded to:
"It is not fitting for a man that Allah should speak to him except by inspiration, or from behind a veil, or by the sending of a messenger to reveal, with Allah's Permission, what Allah Wills: for He is Most High, Most Wise." [42:51]
This is the reason the angels were created. They fit a purpose within the system that Allah (The Exalted) established. They serve as devotees in worship, guardians over humans, record peoples' deeds, deliver revelation, control the weather and vegetation, and this is the reason they serve as guards over Heaven and Hell.
It is also the case that Allah (The Exalted) has created an Arsh (Throne) and a Kursi (Pedestal or Footstool), although He (The Almighty) is not in need of them. Allah (The Glorified and Exalted) is the King of kings. This means that He has the complete Ownership and absolute Dominion over everything. He is not in need of either a Kursi or an Arsh, He has created them as a Sign. The establishment of the Throne and the Pedestal signifies Allah’s Authority and Rule over His creation. These symbols also display His Power, Might, and Greatness to His creation (especially angels and then man and jinn on the Day of Judgment).
2) Everything that has been created has been given some sense of Whom its Creator is, how to worship Him in a manner befitting their creation, etc. This is the same with the creation of Heaven and Hell. This is the reason one reads in the accounts of even a date palm tree having some sense. This is alluded to in the following hadith:
Narrated Ibn Umar (may Allah be pleased with him):
The Prophet (peace and blessings of Allah be upon him) used to deliver his sermons while standing beside a trunk of a date-palm. When he had the pulpit made, he used it instead. The trunk started crying and the Prophet (peace and blessings be upon him) went to it, rubbing his hand over it (to stop its crying). [Bukhari: Book 4: Volume 56: Hadith 783]
On the Day of Judgment, Hell will be filled with humans and then asked whether it is full or satisfied, Hell will answer, "Are there anymore?." Allah (The Exalted) will then have the borders of Hell retract and no one else will be sent into it. No, Hell is not infinite, it simply means the borders will retract from whatever there initial size was.
3) Some advice. There was a Muslim man that would ask the Prophet (peace and blessings of Allah be upon him) ridiculous questions, and Umar (may Allah be pleased with him) would become so upset that he would attempt to silence that man physically.
Some humans, depending upon the personality type they are born with, possess a great deal of wisdom and insight and a high level of intelligence and knowledge, also being dependent upon having acquired a higher formal education. Most "common people" are ignorant, low-educated, and foolish. This is the reason many of them become misguided, suffer from weak faith, and ask foolish questions. Follow the advice of Allah (The Exalted), obey Him and practice the religion and you will get into Heaven. Refrain from making questions or contemplating over matters that would lead young children astray, that frequent this site, or lead yourself astray.
"Freethinking" is best left to the men that have the intellectual capability, insight and wisdom, as well as the broad education necessary for such an undertaking. "Freethinking" for a teenager (that believes he or she knows everything at their young age, lack of experience in life, or lack of a higher education), as well as for the rest of the "common people" will surely lead them to loss both in this world and the Hereafter.
Most people recognize their own intellectual limitations, each individual must draw a mental barrier within their mind and not dwell beyond this point.
And Allah (The Glorified and Exalted) Knows Best.