The term "Daisy Chain" actually applies to the practice of plugging one cab into the amplifier and the second cab into the first cab. Since the industry standard is to use parallel connections for both the jacks in the amp and jacks in the cab, either way you hook it up, the amp will see the same load and give you the same result.
The Rumble 100 however doesn't have an extension speaker or any output at all. It doesn't appear to have any output for an extension cab ans is really only meant to be run with its internal speaker. Same with the Ampeg RB112. However, you can send your Fender sound to another combo such as the RB112 by connecting the effects send of the Rumble 100 to the Effects return of the Ampeg RB112 combo. That will make your Fender Rumble 100 become the "master" amp and the RB112 combo the slave combo. That will send the preamp signal of your Rumble to the Ampeg RB112's power section, bypassing the Ampeg preamp and giving the RB112 a "Fender" sound. If you do it the other way around using the Ampeg RB112 as the master and the Rumble 100 as the slave, you will end up with an Ampeg sound. The sound of the amp primarily comes from the preamp used to send a signal to the power section.
You will need to adjust the volume levels (master control) of each to get the balance you want at the level you want, but that will give you a 200-watt 212 system, which should certainly work for small and medium-size venues. I doubt that will be enough for a large venue but odds are it will be sufficient for most of your venues. The problem becomes though that you really don't have a way to upgrade to be able to play large or outdoor venues without buying another combo and sending effects-send connections to two slave combos from the one master combo. Good news is that any change in the EQ that you make to the "master" amp will automatically go through to the "slave" amp because the master amp's preamp is providing the same signal to the slave amp that the master amp is using itself. You will however have to readjust the levels of each amp if you need to be either louder or softer.
I think your money might be better spent buying either the Rumble 500 or the Ampeg RB210. Both of those combos on their own will work fine for small and medium-sized venues. Both amps will do 500-watts rms into 4Ω. The Rumble 500 puts out 350-watts rms into 8Ω, which is what its internal speakers are. The RB210 puts out 250-watts into an 8Ω load, which is what its internal speakers are. Both of them will work fine for small and medium-sized venues as-is. When playing a large and/or outdoor venue with either, you will need to buy another 210 cab to "daisy chain" to the combo. Both of those combo+extension speaker set-ups will give you a de facto 500-watt, 410 rig, which is enough power and speakers to play just about anywhere.
Currently the Rumble 500 is running about $649 and the RB210 combo is priced at $679 . A Rumble 210 cabinet sells for $500 as does an Ampeg 210 cabinet for the RB210. If you like the Fender sound, get the Rumble. If you like the Ampeg sound, get the RB210. The Rumble 500 and the Ampeg RB210 are different sounding beasts, so if don't like the Fender sound, get the Ampeg. If you don't like the Ampeg sound, get the Rumble 500. Both will do the trick but you can't make the Fender sound like an Ampeg or the Ampeg sound like the Fender.
Additionally, if you want to add your Rumble 100 to either of those you can slave your Rumble 100 to either one to get some extra coverage that the single 210 combos can't handle on their own. That might allow a delay before you find you actually need to buy a second 210 cab.
