A, single, one pine tree? Grow whatever you want
. You are in Las Vegas? You have much bigger problems than a pine tree
In a conifer forest you have very intense shade, such that few things can grow. You have a duff made up of pine needles, which will acidify the soil and narrow the range of what will grow again. In some areas, such as where I live, the woodlands are very heavily dominated by pines that are adapted to grow in a less than optimal environment and which then apply further pressures on what other plants will grow in the area with the combination of shade and acid soil. These places get the name "pine barrens" and I can tell you from
experience they are a rough environment to try and grow anything not
native.
But a pine tree? Look at where the shade falls, choose your plants accordingly. You already noted that your soil is alkaline so the acidity from the needles may be a benefit. I do not recall pine being alleopathic, I think it is just an issue of dense shade and acidic soil, and those don't really apply with one tree and an alkaline soil chemistry