In desktop mode (i.e. not playing games) you will be fine. However, for games 2GB of VRAM is recommended. Also, I don't know of any games that supports dual monitors if the intent is to play games on both at the same time.
Going from 1080p to 1440p will likely mean a 40% drop in frame rates.
Yeah I generally turn off 1 monitor when I'm gaming anyway so It sounds like it'll work out. Thank you!