can loadcomplete create ~100 simultaneious Citrix login and running couple of application instances on each session and measure the load? does loadcomplete support that?
Yes, LoadComplete supports distributed load testing. LoadComplete Remote Agent is used to run load test on remote stations and provide the Master one with the obtained results.
As per documentation, LoadComplete determines the number of Load Agents required to run on this or that machine and manages their instances automatically (https://support.smartbear.com/loadcomplete/docs/testing-with/configuring/workstations/remote-agent/a...).
As for Citrix logins...
a) Remote Agent must be installed on the station in order to be used by Master instance of LoadComplete;
b) As Remote Agent is running as a service, no active user session is required on the remote machines;
c) Consider your LoadComplete licensing (https://support.smartbear.com/loadcomplete/docs/licensing/virtual-users.html, https://support.smartbear.com/loadcomplete/docs/licensing/how-licensing-subsystem-works.html);
d) LoadComplete does not provide any means to manage Citrix or Remote Desktop sessions, so you will have to somehow provide them beforehand;
e) You may consider AWS cloud testing (https://support.smartbear.com/loadcomplete/docs/testing-with/configuring/cloud/index.html, https://support.smartbear.com/loadcomplete/docs/use-cases/load-testing-on-cloud-computers.html)