@Bignose21 

I am fairly sure for some reason they pick up more distant EAP225-Outdoor, rather than pick the nearest & don't even seem to switch very well when they loose again.

Now perhaps more of poor implementation in the individual wifi devices but as not isolated to one type does seem to be a thing.

Ive seen this before with HP Printers.. without going into too much detail it appeared the Printer was starting on channel 1 and looking for an SSID, then channel 2.. channel 3 etc in that order.    Therefore it seen the FAR away AP on channel 1 and just used it immediately.     Moving channel 1 to the AP near the printer solved this.    Few others on the forums have mentioned similar things, it seems to be an IOT issue as generally they are cheaper devices and their WiFi cards are cr4pp7

In answer to more than 8 SSIDS per AP.. simple answer is NO sadly.  That is a physical limit on the chipset inside the AP.    However, thinking out loud here as i havent tried it myself.. if you have more than 8 SSIDs you dont need to have all them on each AP.   Go to AP1 and you can have SSID 1 to 8 broadcasting.   On AP2 you can change this to SSID 9-17   just a matter of selecting / deselecting the SSIDs you require in the vicinity of that AP. 

However... imho the more SSIDs you have the more messy it gets, should be kept to a minimum.  However this is up to you

  @Bignose21 

Why would you simply not do an override on the local AP SSID settings under config?