Hi Ken,
If you currently don't have the room for floorstanders, then I wouldn't outlay the funds for options 2-5, except for a moderately priced integrated at this time.
I agree with others that you should ideally nail down your speaker selection before dropping a lot of money on amplification, unless you know that there is a brand of amplification that you really like, which might justify matching the speakers to your amp.
If you liked the Simaudio Neo 340 over what you currently have, then perhaps that's a good intermediate step, and has the options of selling here at some time in the future or upgrading through your dealer; when you have more room for new speakers.
That said, the options that you listed will all have different sonic signatures. You would need to carefully evaluate each of them to find your preference, and also match to new speakers (or vice-versa); regardless of which option you start with.
I have owned the Simaudio i-5, i5.3, 600i, and 700i (currently using 600i). I like many things about the Simaudio sound, which can sound warm at times, but they aren't the warmest out there. They will show differences between speaker cables and interconnects (and power cords), which will also end up giving you something to do!
Good luck and have fun,
Gary