You can deploy to a different project by using -project flag.
By default, the service is deployed the current project configured via:
$ gcloud config set core/project PROJECT
To override this value for a single deployment, use the -project flag:
$ gcloud app deploy ~/my_app/app.yaml -project=PROJECT
Ref: https://cloud.google.com/sdk/gcloud/reference/app/deploy

Cloud Functions is Google Cloud's event-driven serverless compute platform that lets you run your code locally or in the cloud without having to provision servers. Cloud Functions scales up or down, so you pay only for compute resources you use. Cloud Functions have excellent integration with Cloud Pub/Sub, lets you scale down to zero and is recommended by Google as the ideal serverless platform to use when dependent on Cloud Pub/Sub.
"If you're building a simple API (a small set of functions to be accessed via HTTP or Cloud Pub/Sub), we recommend using Cloud Functions." Ref: https://cloud.google.com/serverless-options

Google Cloud Coldline is a new cold-tier storage for archival data with access frequency of less than once per year. Unlike other cold storage options, Nearline has no delays prior to data access, so now it is the leading solution among competitors.
The Real description is about Coldline storage Class:
Coldline Storage
Coldline Storage is a very-low-cost, highly durable storage service for storing infrequently accessed data.
Coldline Storage is a better choice than Standard Storage or Nearline Storage in scenarios where slightly lower availability, a 90-day minimum storage duration, and higher costs for data access are acceptable trade-offs for lowered at-rest storage costs.
Coldline Storage is ideal for data you plan to read or modify at most once a quarter. Note, however, that for data being kept entirely for backup or archiving purposes, Archive Storage is more cost-effective, as it offers the lowest storage costs.
https://cloud.google.com/storage/docs/storage-classes#coldline