Use SmartFade 1248 to control multi-color RGB fixture?

Yes it's possible and you've pretty much stated how to do it.

Most basic LED lights use 3-6 addresses so you will need a group of channels free. Many of my clients with exactly this set up group their LEDs together by addressing the fixtures the same or by patching several addresses to each channel. Set one channel per fixture address to be controlled. Many fixtures have multiple modes including one that uses a minimum number of addresses for exactly your situation. As you can see keeping the channel count below your 48 limit will be critical. Once you have control over everything then you can set memories and program as usual.

Thanks!

In looking at the jack near the stage labeled "DMX In," I noticed it is a male port. Does that mean it can't be used to connect devices? Or can I use a gender changing cable/adapter to make this work?

Thanks again!

SmartFade has a backup console function. The input signal can be passed through or overridden but only if the console is set to Backup rather than Normal mode. You can worry about that after you buy a more capable console.

As it is labelled "DMX In", it is almost certainly an alternate place to plug in your SmartFade.

You shouldn't connect any DMX controlled lights to it, this would create a Y-split - which might work, or might cause the whole system to become unstable and flicker like a mad thing!

It's quite common to have somewhere on stage to plug in the lighting console, as can be nice to move the desk there for some show or during rehearsals.

I’ll echo Richards warning about creating a DMX ‘Y’ that can cause instability in the dimming system…. One other word of warning before you read more, LED’s and moving lights connected in a ‘non-official way’ to a DMX run can have a nasty habit of shorting power onto the DMX line. Basically if there is an issue with the device and power gets to the data line, you will damage all other devices connected….meaning the DMX output of your board and the DMX input to your dimmers.
All that being said, you would not be the first, or hundredth person, to do something like this.

DMX wire-runs are connected in series. Meaning that the line most likely starts in the booth, runs to the stage ‘DMX in’ and then runs to the dimmers (or other ‘DMX in’ locations).

If you want to ‘take a stab’ at it: You will need to buy or build a ‘gender bender’ to convert the 5-pin male input to a 5-pin female output. For added safety you would ideally connect a DMX opto-isolater between the ‘out’ you have made and the fixtures you are connecting.

You have been official warned! 

See also: https://www.learnstagelighting.com/how-do-i-split-or-convert-dmx/