Probably a good starting point for us is a clear understanding of exactly what you have:
Synths we know - is the radias an TI keyboard versions or not?
How do you interface everything to your computer?
TI Via USB, Radias via USB?
Karma (keyboard) and other non USB midi devices via I assume a USB midi interface?
What audio card/mixer do you use?
Do you use Reason Rewired to Cubase - that in itself will add to yoru headaches - rewire that is. The problem with these two is that reason when rewire still want to contorl all the midi hardware (but not audio). Most this isnt a problem, but you cant get really strange things happening when you are using a DAW contol surface rather than just a midi keyboard.
MIDI clocks - if you want all the midi gear in sync, they (ideally) need to be driven off a common clock. Cubase can provide such a clock. In MIDI there are a couple of types of clock - synths reposne to one type and full sequencers respond to both - one includes song position info, the other is very simple and just send 24 ticks per beat. Is this simple that is recognised by synths as a tempo clock. Something called MIDI clock, or beat clock. It is NOT timecode (MTC), or MMC etc. In Cubase, you can set the beat clock destinations from the Transport menu - sync setup option. This give you a dialog - at the bottom right - tick all the MIDI outs to which a synth that needs sync is connected - this is not needed for the "Virus TI Synth" though.
When Im working with Cubase, I have all of my synths set to external midi clock. When you use Virus Control - that happens automatically. On the Radias - press global, Clock in 4th down on the MIDI page - set to EXT-USB if you are using USB, else EXT-MIDI if you are using a hardware midi interface.
Dont where this otion is on the Karma or Electribe - hmm - you seem to like Korg stuff
The next headache you might have is MIDI feedback loops - ie you try and record something and all hell breaks loose - if so - whats going on is that Cubase by default functions as a midi router - it like to sit between all keyboard and all synths and is routing every midi message it sees back out again, which inturn is forwarding it back in... Often its more subtle -you play a single note and you get two notes the same played toger and they just sound a bit phased.
Most keyboard synths are actually two units - a controller/keyboard and a synth engine. On the synth - if local control is on, then everything you do on the keyboard goes direct to the synth engine, as well as out via MIDI. With local control off - keys go out via midi only and not to the synth engine - Local off is what you generall want to start with in a DAW environment - this allwos the DAW to route what you play from any keyboard to the required synth. Again - you should find this setting in the global config menu of the various bits of gear. Virus Control sets local off automatically. If you are getting MIDI feedback (ie all hell breaksloose when you try and record - then Locla control is on, and midi routing is enabled int he DAW - you cant have both). In cubase the otpn to control this (On by default is in the preferences under MIDI.
Not everything likes to work with the DAW in full control of everything - I generally dont, but everything is often alot easier to use unless you tend to work allmost exclusie with haward and only use the DAW as a dumb recorder for tracking until your ready to work completly inside the DAW.
The audio issue (out of tune) you have - is that with a specific synth? That sounds like the audio was recording at what Cubase thought was 44.1 Khz, but was actually 48Khz and its playing it back at 44.1 without realising it needed to sample rate convert it. If that makes no sense - I assume the electribe can play sample and that there is a pitch control - you know if you reduce the pitch, the sample gets longer? - same thing happening.
The cause - dont know specifically - could even be Cubase is getting confused about the sample rate the card is working at - I have know this happen with some audio interfaces at times. It has sometimes happened with the Virus TI as well.
What sample rate do you normally work at? and are the Cubase default project preference set to be this sample rate? Cubase absolutely hates it when you change sample rates - even between sessions. Best advise - find a sample rate at which everything works and stick to it - never change it.
If you get someone in by the hour - do try and find out alot about them first - be abit of a waste to hand over 200 quid, end up functional, but not actually know what he did or why etc... - Much better to actually learn the basics - particularly the ways - and roughly what stuff does under the hood etc.
Anyway - give us more detail if what you have get there and Im sure people here can help to some degree and help sort out some basic issues.