As far as playing rhythm patterns along with your project, the best “EZ Guitar” software VST that ever was, was Virtual Guitarist 2 which has LONG been discontinued. That said, the sample sets and VSTi’s today are FAR more realistic and offer lots of nuance…the big challenge is to play/program them well, which in many cases is NOT easy.
That said, the best ones I’ve tried recently have been Native Instrument’s FUNK GUITARIST and Impact Soundworks SHREDDAGE 2.
The thing to keep in mind is that you can’t always go by the name of a product and think “that’s not for me” – Funk Guitarist is simply a clean strat, but it has a huge library of chords and you can customize the chords and rhythms however you want. This makes it a good fit for pop, rock (if you run it through your favorite amp sim) or other styles – but it DOES take some WORK to get on with the interface. It’s an amazing instrument, but like most VSTi’s they are kind of designed for keyboard players (IMO) – and they require some concentrated MIDI editing on the back end for everyone else to make use of the keyswitches, velocity levels, and performance nuances that the instrument offers.
Shreddage offers DRY samples, so you can re-amp them any way you want. You want hard and heavy or clean and chorused? Just run it through your amp sim or effects chain of choice. Although Shreddage IS targeted for straight ahead heavy rock rhythm playing – you can adapt it to other styles as well…with enough work 
Some very affordable solutions can be had at Indiginus Sample Libraries. Their acoustic guitars have “strum engines” and overall you can get some good results with them, but in place of keyswitches, they are velocity layer switches.
The bottom line is that you can take the SAME MIDI information and play 4 different guitar VSTi’s and get completely different results depending on how the instruments are programmed. There is no real “easy” solution for virtual guitars, all of the current solutions will require patience, MIDI programming, and time invested in understanding the features of the individual virtual instrument.
Bass would be a LITTLE easier, but real bass players (I am a bass player) do a lot of ghosting, mutes, sliding, slapping the fretboard when closing their hands, etc. And some virtual basses offer all of that – the Scarbee models for KONTAKT are exceptional…but you have to program them correctly to capture all of that. – it’s AVAILABLE in the instrument…but simply playing a line on a keyboard won’t give you that – notes have to overlap for slides and hammer ons, etc… velocities have to be right, etc… but for fundamental lines, an “ez bass” might be a possibility with the right sample set/vsti. Broomstick Bass USED to be a decent little VSTi for that sort of thing, but it was discontinued like Virtual Guitarist. 
Creativity is a Work Ethic.
