Answer: The hydrangeas will need an acidic soil to maintain that blue coloring, and based on your description they are changing color in response to a more neutral or alkaline soil. To counter that, you will need to run some basic soil tests and determine the pH in the bed now. Then gradually add sulfur to make it more acidic. You need to do this slowly to avoid shocking the plants, rewd and carefully follow the label directions. (Some people will recommend the faster acting aluminum sulfate but this can cause aluminum to build up in the soil which is toxic.)
There are many evergreens you could use for foundation planting in sun, ranging from junipers to hollies. I would suggest you work with your local county extension and professionally trained nursery staff to develop a list of plants that would do well in that location and then select the one you like best. You will need to keep in mind overall size of the planting area, any height limitations (eg windows), soil type and moisture levels, amount of wind, time of day the sun hits, surrounding plantings, level of maintenance, your budget, and your overall design goals to make a good choice.
Deer are terrible, in my experience the only truly reliable control is a fence. In the meantime some people report success using the commercially formulated spray-on repellents. You have to apply and reapply per the label directions, and rotating between several products also seems to help. I'm sorry I can't be more encouraging on that.
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