Hi

I have RHEL6.4 on my laptop and using Pidgin to communicate with Mcs Lync users.
Mail is received by evolution POP3 client.

I would like to have below capabilities :
#1. Taking part in teleconferences via Lync on my Linux lapotp
#2. Be available to accept invitations to cetain meeting via mail from MCS Exchange

Is it possible to achieve those 2 above things ?

You don't have lync on your linux laptop, or if you do, don't tell me about it because it's no doubt illegal.
The easiest fix there is probably virtualbox, put a windows image in there and then spawn it for teleconferencing, assuming you can work out the issues of passing the video and sound through the virtual veil, you're golden.
There are a lot of good teleconferencing apps in Linux, they just aren't embedded in MS Lyncs

normally invitation come to my thunderbird account as .ics attachments, if you open it up evolution would probably attempt to import it as a calendar event.