I'll give you my take, for what it's worth. I'm not an expert on Heaven, but have read a lot about it and sat under some very good preaching. I'm speaking of expository preaching where the preacher is reading the Bible and pointing out key points and references.
As I understand it, angels are beings that were created to praise and worship God. I also believe they provide protection for God's children on this earth against the evil spirits who have current dominion over this planet....for now.
I think of an old song we used to sing in church. It goes, "It's a song Holy Angels can not sing. Amazing Grace, how sweet the sound. Yes, it's a song Holy Angels can not sing, I once was lost, but now am found."
As you mentioned earlier in this topic, there will be no sadness or crying in Heaven, but I have no idea if our loved ones check in on us or not. If they indeed do, they would not cry or have sorrow over our trials. Not because they don't love us, but because they have been transformed to be like Christ and have the very mind of God.
Here's something that's crossed my small mind. It's nothing I've drawn from the Bible or been taught. It's just a little Grey Colson idea that may or may not be accurate...
You've probably heard that time does not exist in eternity? I believe that 100%. Even secular scientists now believe there are places where time and space don't exist. I actually think it is possible that once you arrive in Heaven, your loved ones, past and present, could already be there and greet you. In other words, since time will not be an issue in Heaven, I believe it's possible to wake up in Heaven, turn around and see you children, parents and grand children walking up behind you.
That may not be the case at all, but there is no way we can imagine what Heaven and eternity is really like.
Regarding animals, I know it's a delicate subject with many people. I never will forget how mad a female co-worker got at me several years ago for suggesting that animals don't die and go to heaven. You'd have thought I was calling her mother a prostitute
Anyway, the bible does speak of animals as mentioned in earlier posts. I believe that may be very true and I think it would be wonderful, but I don't believe they are our former pets. Here's why...God created all the animals and the foul of the air as mentioned in Genesis, but ONLY into to Man did he breath the "breath of live" which was his soul. I believe that animals have knwoledge of God, but not a personal relationship with Him because they lack a "soul".
Just my little take on it.