what's the delta between these and the existing templates?

In this case, the diff between x86/ppc64le isn't very much:

#diff nodejs.json nodejs-ppc64le.json
9c9
< "tags": "quickstart,nodejs",
---
> "tags": "quickstart,nodejs,ppc64le",

#diff nodejs-mongodb.json nodejs-mongodb-ppc64le.json
445,446c445,446
< "description": "Version of MongoDB image to be used (3.2, 3.4, or latest).",
< "value": "3.4",
---
> "description": "Version of MongoDB image to be used (3.6 or latest).",
> "value": "3.6",

#diff nodejs-mongodb-persistent.json nodejs-mongodb-persistent-ppc64le.json
9c9
< "tags": "quickstart,nodejs",
---
> "tags": "quickstart,nodejs,ppc64le",
461,462c461,462
< "description": "Version of MongoDB image to be used (3.2, 3.4, or latest).",
< "value": "3.4",
---
> "description": "Version of MongoDB image to be used (3.6 or latest).",
> "value": "3.6",

LGTM, thanks.