Can you work with Vim on iPad Mini with an external keyboard? I'm considering to buy an iPad Mini and use it -- among other things -- for programming using Vim. I would connect via SSH to a Digital Ocean server and start Vim there. I would use an external (physical) keyboard when working with Vim.

Which app should I use on the iPad to get the best VIM experience over SSH and which issues (e.g. due to keyboard layout) I have to expect?

PS: Note that I don't intend to use the iOS port of Vim.
I use Prompt 2 to connect over SSH to my server. It's a paid app, but I never had an issue with it, it's really reliable. If your connection is good enough you won't appreciate any lag. Vim works great with it.

Can't tell you about external keyboards.