Nothing in Scripture explicitly says infants go to heaven. But the evidence presented from Scripture in the two links provided shows this is a reasonable understanding of Scripture in this matter.
Certainly, I think it more likely that infants are given special treatment by God to get into heaven upon death than thinking that infant baptism will actually bring them into heaven upon death, since we know the scriptures that speaks about baptism speak to believers – regardless of your understanding of water baptism and baptism of the Holy Spirit. And infants are not believers in Christ, as they have not heard and understood the Gospel.
Additionally, it is not infant baptism that sanctifies children, it is the parent’s sanctification that sanctifies the children and unbelieving spouse.
1 Corinthians 7:14
14 For the unbelieving husband is sanctified by the wife, and the unbelieving wife is sanctified by the husband: else were your children unclean; but now are they holy.
As for water baptism, I still hold the evidence shows that this is an expression of the faith that saves us, as is calling on the name of the Lord and confessing Jesus as Lord. There are too many examples where we are told to believe to be saved that do not mention the need for water baptism ((Luke 7:50; John 3:16-18; Acts 10:39-48; Acts 16:31; Titus 3:5; Ephesians 2:8; 2 Thessalonians 2:13), that it is by grace, not a work.
Example of being baptized with water, and not having received the Holy Spirit: Acts 8:14-17.
Example of being baptized with the Holy Spirit (“Holy Spirit poured out”), and not having received water baptism: Acts 10:39-48; Acts 11:15-18 in describing the previous.
Yes, there are instances where we are told to call on the name of the Lord (Romans 10:9-15), or confess the name of Jesus (Acts 2:21), or be baptized (Acts 2:38-39; Acts 22:16). But there are too many instances where it only mentioned we are saved by faith. The only thing all the different ‘formulas’ and examples have in common is faith. It is the faith that saves us, and the actions that give evidence to the faith being real.
Water baptism is an expression of faith, just as confessing Christ, or calling on the name of the Lord. These things show we have faith, and show obedience. It is the Christ who saves us because of the faith we have in Him and His saving work, which we show by our actions. If we do not do the action, then we must question if we have faith.