Fallout Wiki on the quest My Kind of Town (finding a sheriff for Primm) says the following:

If you have ED-E with you when you go talk to Beagle after freeing him, after asking about where to find a new sherriff, everyone in the Vikki and Vance Casino will start attacking ED-E, though they won't become hostile toward you unless you shoot them.

I have usually quick-fixed this quest by installing Primm Slimm as the sheriff and then fixing ED-E. This time, I want to try an NCR or a Meyers solution, but I don't fancy going all the way to the Mojave Outpost or into the NCRF alone. My character is kind of weak (ST4, carrying capacity 190), and weight management is a major issue.

Can anyone confirm whether it's "safe" to fix ED-E before finishing My Kind of Town?

It doesn't take that long to fix EDE, free Beagle, and then go talk to him. (you can free Beagle, leave the hotel and go talk to him before cleaning out the rest of that place).

While the wiki is an awesome place for info, remember that (especially) the bugs aren't always things that affect every player. I hear a lot about ED-E troubles, but I haven't had many of them, including this one, in my game. It's probably one of those things that hits some, doesn't hit others...thus no one can really say if it's going to be 'safe' for you specifically or not.