I was taught that Mormons weren’t Christian because of the things you mentioned, plus a whole myriad of other differences. Christian principles are almost exclusively faith based. Believe in Christ and repentance with certainty, you’ll be fine. TCoJCoLDS (wow even condensed, it’s a pain to write) places a lot of value on “works”. Completing the right tasks (missions, temple duties, marriage, church callings etc etc etc) helps get you to heaven and exaltation.
That's a common complaint from evangelicals in my experience, but is often blown out of proportion. Mormons (ha, see what I did there) don't believe we earn our way to heaven, we believe that we get to heaven by following Jesus... and there are certain things that Jesus has asked us to do so we should do them. See the difference? The only works that are required in some sense are symbols of covenants--such as baptism--and have a mechanism to be done in the hereafter (for example through baptism for the dead), and so even the "required" actions aren't actually required in this life.
However, I will say that from what I've read from church teachings/talks from the past, works did used to be over-emphasized. I believe this was likely in reaction to evangelical teachings that minimized works and went to the other extreme of "once saved/always saved despite what you may do thereafter". That, in my opinion and that of the LDS church is flawed doctrine and should be corrected. But certainly in recent years, church leaders have mostly stopped emphasizing those differences and have more often emphasized the grace of God and how works alone profit us nothing without Christ. See here, for example, for an excellent talk by Dieter Uchtdorf (a counselor to the church president at the time) in 2015:
https://www.lds.org/general-conference/2015/04/the-gift-of-grace?lang=eng. That really gets to the core of LDS belief about faith vs. works, and I strongly recommend you read it.
Which leads to the whole man to god ideology, which is something so inversely different from Christianity that to call it Christian seems strange. If there are an infinite number of worlds, and gods, are there then an infinite number of Jesuses that came to pay for sins? Are all man gods required to send their sons down on their newly created worlds to pay for the new population’s sins? I’m genuinely confused by the topic.
Maybe this isn't the right thread for this discussion, but I'll tackle it. The only doctrine about that in official LDS canon is that men can become like God. This is actually closely related to the doctrine of deification (aka divinization) held to some extent by many mainstream Christian groups. See this article, for example, which gives summaries of the views of various Christian groups, including LDS/Mormons:
https://en.wikipedia.org/wiki/Divinization_(Christian). Mormons take a more literal view of "becoming like God" than do most other Christians, but it's not like this is foreign doctrine.
Now where LDS doctrine goes farther is in speculation that, if we can become like God, did God start out like us? That doctrine was taught be Joseph Smith in his "King Follett discourse", but unfortunately he was murdered before he could explain the ramifications of the idea, nor how it could/should be reconciled with statements in scripture about how God is eternal, etc. And it wasn't presented to the church as scripture. So the idea has certainly been around in the church, and is even discussed in Sunday School classes and the like from time to time, but it's not canonical doctrine in the same sense that "men can become like God" is.
So, with regards to your particular questions there is no actual LDS doctrine and it would just be speculation to answer them. I won't let that stop me though.

I personally don't believe in an infinite number of Jesuses nor that once we become like God that we will need to send our sons anywhere to pay for sins of our own spirit children.
On top of all that, Baptism for the dead, temple ceremonies, a well observed tie to masonry (JS’s Masonic past, relics, alters, chants, handshakes, garments, symbology, etc) all lead to Christians not wanting to include LDS as Christian.
I'll mention that (as you probably know) baptism for the dead was practiced by some of the early Christians, and it's lack of practice in today's Christianity is seen by LDS church members as evidence of an apostasy. With regards to other temple ceremonies you are no doubt correct--there isn't evidence of the in the early Christian church, and they very likely seem odd and different to other Christian groups. But more important undoubtedly (at least in my opinion) is the Church of Jesus Christ of Latter-day Saint's (had to spell it out at least once.

) claim of being the only true church, i.e. the only organization which possesses the needed authority from God and Christ to function as a church...which has as its corollary that the other Christian churches are deficient in some ways. I think that's what really rubs the other churches wrong, and it's in retaliation of that (at least in my opinion) that some of them don't want to recognize us as a Christian church in our own right.
I don’t really believe in any of that stuff, but I’m the sort of atheist that feels that if religion helps you find purpose and peace without harming others, I support you and your life choices.
I like that. I think that's the type of atheist I would be.
