Actually, those verses in no way state that heaven's inhabitants hear us.
Psalm 103:20-21 Bless the Lord, O you his angels, you mighty ones who do His word, hearkening to the voice of His word! .Bless the Lord, all His hosts, His ministers that do His will!
Psalm 148:1-2
Praise the Lord! Praise the Lord from the heavens, praise Him in the heights! Praise him, all his angels, praise him, all his host!
These verses would make no sense if those in heaven could not hear us.
Of course they would because all they are doing is telling us what the angels are doing. The second one, out of Psalm 148, doesn't say a thing about angels being able to hear us, only that they are praising God.
What they state is that the angels are doing GOD'S bidding, hearkening to the voice of HIS word.
None of the other verses you posted say that those in heaven have the power to either hear us or answer our prayers.
God has promised in Scripture that HE will hear and answer our prayers HIMSELF. If that's the case, at the very least, there's simply no need to pray to saints for anything. Not to mention that time dedicated to praying to saints is time taken away from praying to God.