Using iPad to build Point of Sales system

Well, the unfortunate thing here is I'm the system integrator and vendor here...

I'm pretty sure that each piece of the hardware I want to connect will work if its connected one-to-one with iPad as I have got the SDK, but I'm not sure if everything can be connected simultaneously through a USB hub which at the same time needs to charge up the iPad. Through my research online, I've only managed to get a confirmation that iPad is able to charge with a Power Delivery charger and use a USB keyboard/mouse through a USB-C Digital AV Multiport Adapter

(https://www.apple.com/shop/product/MUF82AM/A/usb-c-digital-av-multiport-adapter), but not until a complex scenario that I've elaborated as above.

Anyone with similar experience could share their thoughts?

Appreciate the help!

Thank you for your suggestion @celliott147.

We had looked into Socket Mobile SocketScan, and also Star Micronics wireless receipt printers which are the more popular brands, but it is beyond our client's budget, whom is doing a small business. Socket's hardware easily cost 5 times the price of what we had proposed, and these hardware are from renowned brands (Epson, Zebra). Also a wired solution is likely to have more stable connection due to lesser signal loss, and there's no need for mobility of these hardware around the client's retail store. As for payment terminal, we are working with a payment vendor who will pass the token to our own POS app via bluetooth, so this is probably not an issue for us.

Of course, I could take a risk by getting all the shortlisted hardware and try them out, after all it's either make or break, but it would be better if I can get a better picture from an Apple Product Specialist (but apparently they do not have the answer), or any retail solutions experts that had faced similar experience.

it is custom POS app that we are building.

i took a bet and got the ipad 8th gen, the currently cheapest brand new model available in my location. fortunately, most of the requirements work fine (ipad is charging, barcode scanner is able to scan, screen is duplicated via hdmi. the only thing i couldn't do is to have a second screen (like windows extend mode).

Thank you for the enlightenment @celliott147.

I would love to do so, but there's a tight cost constraints on the hardware (as mentioned it is for a small business), so I guess we'll have to work with one screen for now (ie. pass the iPad to customer whenever needed). I will keep this idea, and suggest to future clients with a bigger budget to work with.