Hello Dhruv.Parekh,
Thanks for your question.
100 function app limit applies specifically to each Premium Plan, not your overall subscription. You can create additional Premium Plans to scale out.
5000 Function Apps per Subscription is a hard limit across all plans in your subscription.
Memory Allocation: fixed maximum memory is 3.5-14 GB for premium plan depending on the SKU. So no you cannot allocate 1GB
Please let me know if you have further questions.
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