Welcome to Microsoft Q&A, thank you for posting your question here!
I found three questions and I would like to break it down for proper understanding.
Your question 1: Is on-premises blob storage supported by Azure Stack Hub Development Kit?
Answer: Yes, on-premises blob storage is supported by Azure Stack Hub Development Kit. You can find more information about it in the following link: ASDK ON-PREMISES STORAGE
Your question 2: If on-premises blob storage is supported by ASDK how much blob storage will we get with minimum hardware requirements as mentioned in the link provided?
Answer: According to Microsoft’s documentation on Azure Stack Development Kit (ASDK), the minimum hardware requirements for ASDK include 4 disks with each disk providing a minimum of 240 GB of capacity (SSD or HDD) for general development kit data1. However, I couldn’t find any information on how much blob storage you will get with minimum hardware requirements.
If you have any other questions, you can read more from this link: ASDK requirements and considerations
Your question 3: Can we customize how we want to split storage between block and blob storage while using ASDK?
Answer: Yes, you can customize how you want to split storage between block and blob storage while using Azure Stack Development Kit (ASDK). You can use the Azure Stack Development Kit (ASDK) to deploy an Azure Stack integrated system that includes a block blob storage account. You can then use the Azure Stack portal to create a new storage account and specify the amount of block blob storage you want to allocate. You can also specify the amount of page blob storage you want to allocate.
Block blobs are optimized for uploading large amounts of data efficiently. Block blobs are composed of blocks, each of which is identified by a block ID. A block blob can include up to 50,000 blocks. Each block in a block blob can be a different size, up to the maximum size permitted for the service version in use. You can read more here: Understanding block blobs, append blobs, and page blobs.
I hope this is helpful.
Regards
Sina