There are people in Heaven - NOW
Rev.19 And after these things I heard a great voice of much people in heaven, saying, Alleluia; Salvation, and glory, and honour, and power, unto the Lord our God:
Yeshua said there are people in heaven:
Matt.11 Verily I say unto you, Among them that are born of women there hath not risen a greater than John the Baptist: notwithstanding he that is least in the kingdom of heaven is greater than he.
Luke.7 28] For I say unto you, Among those that are born of women there is not a greater prophet than John the Baptist: but he that is least in the kingdom of God is greater than he.
Matt.5  Whosoever therefore shall break one of these least commandments, and shall teach men so, he shall be called the least " in ", (which means by, among ) kingdom of heaven: but whosoever shall do and teach them, the same shall be called great " in ", (which means by, among ) the kingdom of heaven
2Kgs.2  And it came to pass, when the LORD would take up Elijah into heaven by a whirlwind, that Elijah went with Elisha from Gilgal.
 And it came to pass, as they still went on, and talked, that, behold, there appeared a chariot of fire, and horses of fire, and parted them both asunder; and Elijah went up by a whirlwind into heaven.
The Greek word G1722 en " in" means:
A primary preposition denoting (fixed) position (in place, time or state), and (by implication) instrumentality (medially or constructively), that is, a relation of rest (intermediate between G1519 and G1537); in, at, (up-) on , by, etc.: - about, after, against, + almost, X altogether, among, X as, at, before, between, (here-) by (+ all means), for (. . . sake of), + give self wholly to, (here-) in (-to, -wardly), X mightily, (because) of, (up-) on, [open-] ly, X outwardly, one, X quickly, X shortly, [speedi-] ly, X that, X there (-in, -on), through (-out), (un-) to(-ward), under, when, where (-with), while, with (-in). Often used in compounds, with substantially the same import; rarely with verbs of motion, and then not to indicate direction, except (elliptically) by a separate (and different) prep.
Thayer Definition: Part of Speech: preposition - 1) in, by, with etc.
Rev.5[ 3] And no man in heaven, nor in earth, neither under the earth, was able to open the book, neither to look thereon.
Heaven and Hell are spiritual places. Yes there are People in Heaven & Hell Today, even as you read this!
Here a a few scriptures:
Luke.23  And one of the malefactors which were hanged railed
on him, saying, If thou be Christ, save thyself and us.
 But the other answering rebuked him, saying, Dost not thou fear God, seeing thou art in the same condemnation?
 And we indeed justly; for we receive the due reward of our deeds: but this man hath done nothing amiss.
 And he said unto Jesus, Lord, remember me when thou comest into thy kingdom.
 And Jesus said unto him, Verily I say unto thee, To day shalt thou be with me in paradise.
People in Hell today
Luke.16 There was a certain rich man, which was clothed
in purple and fine linen, and fared sumptuously every day:
 And there was a certain beggar named Lazarus, which was laid at his gate, full of sores,
 And desiring to be fed with the crumbs which fell from the rich man's table: moreover the dogs came and licked his sores.
 And it came to pass, that the beggar died, and was carried by the angels into Abraham's bosom: the rich man also died, and was buried;
 And in hell he lift up his eyes, being in torments , and seeth Abraham afar off, and Lazarus in his bosom.
 And he cried and said, Father Abraham, have mercy on me, and send Lazarus, that he may dip the tip of his finger in water, and cool my tongue; for I am tormented in this flame .
 But Abraham said, Son, remember that thou in thy lifetime receivedst thy good things, and likewise Lazarus evil things: but now he is comforted, and thou art tormented.
 And beside all this, between us and you there is a great gulf fixed: so that they which would pass from hence to you cannot; neither can they pass to us, that would come from thence.
 Then he said, I pray thee therefore, father, that thou wouldest send him to my father's house:
 For I have five brethren; that he may testify unto them, lest they also come into this place of torment.
 Abraham saith unto him, They have Moses and the prophets; let them hear them.
 And he said, Nay, father Abraham: but if one went unto them from the dead, they will repent.
 And he said unto him, If they hear not Moses and the prophets, neither will they be persuaded, though one rose from the dead.
1Pet.3[ 19] By which also he went and preached unto the spirits in prison;  Which sometime were disobedient, when once the longsuffering of God waited in the days of Noah, while the ark was a preparing, wherein few, that is, eight souls were saved by water.