1) If the locus sms receiver would work, then it would be possible to send location from locus by using share feature.
1a) The locusSMS is receive only
2) Setup should both ways, however the app can still leave the sms into inbox. It was not actually designed to work both ways,
3) In preferences the options are for internal gps, how often the gps on the phone should try to get location from satellites.
3a) No, they limit only how aggressive is the gps chip.
3b) The periodic uptate on main screen will to automatic updates on certain intervals. It is limited to 20 updates.
4) Auto send is very poorly named, I'm sorry for that. Most of the strings I have written were first in Finnish -> translated to English. It should say: Automatically show received points in Locus (No notification of received point).
5) Probably a bug. I will try to put a beta version to here, where is most of the bugs are fixed.