2 Corinthians 5:21 says we were made the righteousness of God in Him.
Correct. Christ's perfect righteousness as the Surety of God's elect was imputed to them. Likewise, all of the sins of God's elect were imputed to Christ and He paid all of their sin debt.
There are no goats, predestined to eternal punishment
The Bible says there are.
Romans 9:21 Hath not the potter power over the clay, of the same lump to make one vessel unto honour, and another unto dishonour?
Yes the OT saints had to wait to be made perfect,
Nope.
Those before the cross had the gospel preached to them just as those after the cross.
Hebrews 4:2 For unto us was the gospel preached,
as well as unto them.
Hebrews 4:6 They to whom it
was first preached.
(emphasis mine)
Everyone who is saved is imputed with the righteousness of Christ.
David lived
before the cross.
Psalm 32:2 Blessed is the man unto whom the LORD imputeth not iniquity.
Lot lived
before the cross.
2 Peter 2:8 (For that righteous man dwelling among them, in seeing and hearing, vexed his righteous soul from day to day with their unlawful deeds).
Abraham lived
before the Christ.
John 8:56 Your father Abraham rejoiced to see my day: and he saw it, and was glad.
"
and was carried by the angels into Abraham's bosom: by Abraham's bosom is meant heaven, a phrase well known to the Jews, by which they commonly expressed the happiness of the future state: of Abraham's happy state they had no doubt; and when they spake of the happiness of another's, they sometimes signified it by going to Abraham."
- excerpt from John Gill's commentary on Luke 16:22
"
God having provided some better thing for us,.... Not a better state of the church, in such respect, as to be free from suffering reproach and persecutions; for this is the case of saints under the New Testament as under the Old; nor the felicity of the soul after death; nor any greater degree of happiness in the other world; nor the perfection of blessedness in soul and body; things common to all believers; but Christ, as now exhibited in the flesh: Jesus Christ was the same in the yesterday of the Old Testament, as he is in the present day of the Gospel dispensation; he was slain from the foundation of the world; and the saints then were saved as now, by his grace and righteousness: only with this difference between them and us; they had Christ in the promise, we have him himself that was promised; they had him in type and shadow, we have him in reality and truth; they believed in, and were saved by Christ, who was to come; we believe in him, and are saved by him, as being come. Hence our case is, with respect to these circumstances, better than theirs; we have a better covenant, or a better administration of the covenant of grace; we have a better priesthood, and a better sacrifice; the Gospel is dispensed in a better manner, more dearly and fully: our condition is better than theirs; they were as children under tutors and governors, and were under a spirit of bondage; but we are redeemed from under the law, and are clear of its burdensome rites, as well as of its curse and condemnation; and have the spirit of liberty and adoption. And this God has provided for us in his council and covenant: for this denotes God's determination, designation, and appointment of Christ, to be the propitiatory sacrifice for sin; and has respect to the nature and circumstances of his death, which were fixed in the purposes of God; as well as the time of his coming into the world, and the season of his death; and in all this God has shown his great goodness, his amazing love, and the riches of his grace: and his end herein is,
that they without us should not be made perfect; the Old Testament saints are perfectly justified, perfectly sanctified, and perfectly glorified."
- excerpt from John Gill's commentary on Hebrews 11:40.