Yes you can open a new account with interbankfx using MT4. I have a mini with them. And yes you can trade micro-lots on the interbankfx mini platform. If you have a mini with them the lot sizes work like this:

setting lot size to 1.0 lots = 1 mini lot (0.1 lot or $10K lot)
setting lot size to 0.1 lots = 1 micro lot (0.01 lot or $1K lot)
setting lot size to 10.0 lots = 1 standard lot (1.0 lot or $100K lot)