The only Emotiva surround receiver that came out (that I know of) is the Fusion 8100. Keep in mind that this only provide 65 watts per channel when all channels are driven (or 110 watts per channel if you ONLY use left/right). The only way you’d get 250 watts per channel is if you connected an external amplifier to the Emotiva receiver pre-outs.
I would be careful about choosing the Monitor Audio speakers as they drop down to 3 ohms impedance in the midbass area. The power supply of the Emotiva receiver is really not large enough to handle 5 speakers with this kind of impedance. What happens is a reduction in bass/midbass strength and the speakers will sound lean or lacking bass. Sure, you can do it, but you won’t be driving the Monitor Audio to their best advantage.
https://www.stereophile.com/content/monitor-audio-silver-8-loudspeaker-measurements
The Elac speakers are actually a very good choice for your receiver, as their impedance curve is on the high side and only drops down to about 6 ohms minimum (or 5.4 ohms based on the F6 specs). The Elac would be easier for the Emotiva to drive and, ultimately, you’ll probably get better results. They have been said to sound very nice as well (the ones designed by Andrew Jones).
The Kef R500 are 8 ohm, but minimum 3.2 ohm impedance. Be careful with these also.
In general, if you look at other speakers, look for 8ohm speakers and avoid the 6ohm or 4ohm speakers. Research the impedance curves (if they are tested by somebody like Stereophile or others), and make sure the impedance doesn’t really drop down below 6ohm or so.
The Paradigm Prestige appears to drop down to about 4 ohms or so (based on the 95F model).