Visits from deceased
Many of the people I know believe that they have been visited by deceased loved ones in the form of birds or other "signs." This seems to bring them comfort. I have told them I believe that while birds or other things can be beautiful reminders of our loved ones, they don't come back for a visit. They tell me they "felt" it and it was real. How can I lovingly let them know this is not true without making them feel their grief for the person all over again. I know we are to "speak the truth in love." I don't want to drive them from Jesus by making them angry at me so they won't hear me.
You are doing well in carefully listening to your friends, tactfully asking them questions and responding in love with Scripture. You do not specify whether or not your friends claim to embrace Christianity. If that is the case, it would be fair to ask them where the Bible speaks of reincarnation. (It does not, of course.) The Bible does state that “Man is destined to die once, and after that to face judgment” (Hebrews 9:27). The Bible does describe people who have been judged as being in heaven or hell, with no possibility of leaving either place (Luke 16:19-31). The comfort we have about loved ones who have died in the Christian faith is that they are in the presence of the Lord (Revelation 14:13), not that they have returned to us in some other form. Statements from God in the Bible override any of our feelings to the contrary.
If the friends you reference are not Christians, then their ideas of death are likely associated with many other wrong ideas. That requires patient listening and witnessing on your part. Point them to Jesus who alone gives eternal life (John 3:16; 11:25-26).
In either case, you partially answered your own question in that you want to “speak the truth in love” (Ephesians 4:15) to these friends and all whom you meet in life.