Sorry vlad2005 - missed your questions in the first post.
As to your variants.
they're all OK
#1 Probably OK, but doesn't specify bandwidth or modulation method.. unhelpful, and though the quoted sensitivity is -116dBm, without this info it's hard to guess what that means. I approve of the shielding can, though. The transmitter's 25mW is about +14dBm - a lot
but #2 OK as well if you buy tx/rx pairs they should work well together. +11dBm tx power is plenty - you should get reasonable range - at least 50m in free air.. And -110 sensitivity for it's bandwidth is reasonable. It implies a noise figure in the region of 12dB, which isn't brilliant but usable.
Neither generate or interpret the codes - you'll have to do that with an arduino, for example.
#3 is much the same as #2 .
The helical antennas described in #2's advert should be fine, with a gain a little less than a 1/4 wave, but much more compact.
You could make one and try it with your existing receiver .
regards
Allan