I’d urge you to give Modo Indie another shot. I started with Maya LT and switched to Modo Indie myself, and I freaking love it. Once you get your mind around it, it’s so much more intuitive to use. I’ve never really run into any issue when exporting my content (as FBX) from Modo into UE4. Just be sure to include smoothing groups when you export. You can enable that by going to [System]->[Preferences]->[File I/O]->[FBX 1/O] and checking ‘save smoothing groups’.
As to the grid, I’m not 100% certain I understand what you’re referring to here. Do you mean the work plane? If so, you can turn this off by clicking the “gear” icon in the top right of the display port, selecting [Visibility] and unchecking ‘Show Work Plane’. By advised though, the work plane is really useful once you understand how it is used. Basically, anything you draw, will start on the work plane. You can align it to anything you want, but by default, it aligns perpendicular to your viewing axis.
Finally, I’m also not 100% clear by what you’re referring to in regards to the selection centre. I assume you’re talking about the action centre though. By default, these are set to automatic and will show up in the most relevant spot when you open a tool. Usually, this is the centre of the item, polygon, edge, vertex, or whatever you’re working with. Clicking a second time moves the action centre to where you clicked. These, like the work plane, are actually really useful once you understand what they’re for and how they work. I’d suggest watching a video demonstration to get a good idea for how they can improve your workflow.
Hope that helps! Good luck.