I think that even if [deck drop instance] is clearer than [dockerfile image container] it would be better to use [dockerfile image container] it's the standard set forth from docker, sticking to the standard makes interoperating easier for everyone.
I'd have to agree that the standard Docker terminology would be much preferred. Your business covers what is a pretty cutting edge, advanced concept right now. Your customers are likely to be at least somewhat understanding of the standard terminology. Your custom terminology tripped me up as well, despite having a reasonable grasp of the higher level Docker terminology.
Other than that, this looks great! I'm excited for you guys.
I'm in a similar problem space to you. After a year of defining my own 'simpler' terminology, decided to abandon it in favour of being consistent with the more popular albeit complex terminology.