Clone gate and garage access Remote
Likely there is not a learning remote for this, since they are different frequencies and protocols.

There are a couple of options, though:

Add a "Security+ 2.0" compatible receiver to the gate

Depending on the actual gate used, if you can wire in a universal receiver, then you can link the Liftmaster remote with it. Would need details on the gate control hardware to help with that (probably best to ask a separate question).

Of course, if "HOA" == "Home owner association" == you can't modify the gate, then this may not be an option. Maybe you could get the HOA to wire this in, as likely other residents would benefit because Liftmaster is a pretty popular brand (also sold as Chamberlain and many Sears brands, and probably others). 

Custom-build a remote

Looks like the Linear remote is already a "keychain" remote. From there, get a normal Liftmaster visor remote, and try to fit the contents of the linear into it, or potentially get a Liftmaster keychain remote (smaller) and fit both of them into a visor-style clip.