Hey Outrageous,
I'm also based in Canada! Been playing classical theremin for a year and a half. Great to see a new Canadian face around here!
I'm actually selling one of my starting instruments, a Moog Etherwave Standard (the one you mentioned - this and the Plus are generally the recommended instruments for beginners) at $570 CAD. I'd actually be willing to go a little cheaper - I'm in a position where I need to move it quick, as money's a bit... you know how things can be right now. Comes with the gig bag too, and both are in exceptional condition with essentially no cosmetic wear. Would that be up your alley?
EDIT: Oh! As I was writing this, I realised someone actually recommended my instrument to you! Works out pretty well...
To answer the above question(s) with my seller's bias aside, I also have no experience with the LV-3P, but I've never heard of it from other thereminists. Generally, when professionals talk first instruments for classical players, they talk about the Etherwave Standard/Plus. As someone who 'grew up' in my theremin journey playing a Plus at the $900 CAD pricepoint, I would absolutely recommend a Standard/Plus. (The difference between them is the Plus has MIDI capability and a headphone jac, which in my opinion... doesn't sound all too great, but is there if you want it and have a pre-amp to make it work. In all other aspects, they are the same.)
They're very sound instruments, with pretty good linearity of the pitch field (uncommon on lower-priced instruments), a responsive volume antenna, easy tuning, and timbral versatility that you come to appreciate almost immediately. Plus, the sound on them is quite nice. In short, they're well suited to precise melodic playing and expression, useful for stuff like classical, pop, folk, etc. Some professionals even play these instruments into their careers - sometimes with some small, commercially available modifications (like the ESPE01 module by Thierry Frenkel - had that added to my Etherwave Plus 8 months after I got it, and I love it).
Either way, really cool to see another Canadian theremin player, and I wish you the best of luck making a selection here. Hopefully some of that insight on the Standard/Plus was helpful! (And as you know, I'm selling one of these (listing's up ^ there) right now, and I'm flexible on it, so feel free to shoot me a message if you like!)
- Colin