Track and trace geolocation & temperature with blockchains on a supply chain

For my internship, I need to implement a blockchain based solution to manage a drug supply chain. The management of this supply chain implies to track-and-trace (geolocate) a drug on the chain, but also to monitor the storage temperature to see if the cold chain is respected. For that I also intend to use IOT, where a device will feed information on the blockchain solution. However, I have a few questions that I can’t find easier.

The first one is that I don’t know if I should use ethereum or not, since each time that a new block is added (the block representing the update on the information about the product on “real-time”) I will to use money. Is there any solution for that? Or do I need to create a blockchain with javascript?

The second question is that I absolutely don’t know from where to begin in order to implement IOT on the block chain. I searched on research site, but they only talk about it, without presenting any example…

The third one is more a confirmation than a question since I want to know if my idea to use an IOT to track and manage products on a supply chain can be done on a wide scale, since the bigger a blockchain the slower is the time to add a block because of the consensus mechanism. So it means that my “real time” tracking on truly be “on time” since there would be a waiting time before the block is added to the blockchain. If the time is just a few seconds to minutes, then there is no problem, but because the number of block will rapidly increase because of the real time tracking (1 block each minute for each storage or transport vehicles I was planning for) that this problem of scalability makes it impractible.

I’m thanking anybody in advance who will help me solve these questions.