Yes, but a lot of client developers have said they won't support RS3. They claim it is a massive project and really not worth it for the small amount of users. Whether RuneMate see it differently remains to be seen ;)
Probably. RS3 is such a small proportion of the botting community many client developers may feel like it's not worth it. RuneMate works differently to other certain bots (that have confirmed they will not support NXT - ever) so it is certainly possible.
I only play (and bot) RS3 - and I'd...
They removed it ages ago, not with the new update. You can run it from Ctrl + R from within Runemate. Not much point though, tomorrow is the last day then you'll no longer be able to login.