I purchased ten 5 ft arbivata from a retail store and planted a week later. Eight are looking good but two have have started drying out. I have watered daily and nothing is getting better How can I save these?

There could be differences in soil or the condition/quality of the root systems on the two that are not doing well. Watering daily is likely too much water and that will cause roots to rot in the soil. Interior needle lose is expected on a newly transplanted evergreen, but not out to the tips. tip die back is also not normal. if the needles are brown but the twigs remain green, there is a chance of new needles being produced. Once the twigs are brown, there is little recovery. If there is a warranty involved, notify the retailer as soon as possible.