Upvote:6
The premise to your question is that "the word eternal might mean continuing forever from some point in time." Just so you know, this is a fairly ambiguous starting point.
There are some contexts and perspectives where the meaning of the word eternal is only no end, but others where eternal means no beginning and no end. And this is not necessarily specific to LDS theology.
For example: from our perspective as mortals, one's eternal life and salvation begins after the resurrection. Thus, eternal life, in a sense, has a beginning. Theologically, you might argue that that "beginning" is in Christ, who is without beginning and without end, and from God's perspective, it has always been that way and will always be that way because it is an absolute truth.
You see, there are many ways to perceive eternity and to try to understand it and learn from the scriptures. For instance, where one scripture says that God is the same forever, and another says that there is eternal progression, are talking about two different things. One way to approach the scriptures is to try to find contradicting passages, and if you find some, then they must not be true. Another way to read scriptures is to believe that they are true and then adjust our learning according to what they say.
Ultimately, eternity is a concept that our mortal minds cannot fathom, so precise and universal definitions are hard to come by. These minutia do not matter too much to Latter-day Saints. The scale of eternity is humbling to consider, and even being able to comprehend that we cannot comprehend it is enough to help us learn about God.
In short, yes, those scriptures are consistent with LDS doctrine.