Hi Welcome to the forum!
Take a closer look at the MAX Transit Duo CAt12 on Primecare. Perconally I would buy that rather than a HD2 Mini. Its a great platform and cheaper. With the annual primecare subscription it supports speedfusion too.
If you want to use speedfusion for bonding you need another appliance. For your use case that should either be Peplinks own SPeedfusino CLoud service, or you could roll your own in Vultr. I would recommend Speedfusion Cloud as you’re new to this stuff, you could always change later.
Learn more about Speedfusion Cloud here SpeedFusion Cloud Instructions - Safeguarding Your Connectivity
Speedfusion is a VPN technology. When you use Speedfusion your traffic passes over a bonded VPN between you and teh remote appliance (be that Speedfusion Cloud, or a Fusionhub Solo hosted on Vultr).
No. Your company VPN will just see an internet connection. Your public IP will change (to that of the hosted service you connect to) but nothing else does as far as your applications are concerned.
The MAX Transit does have AC wifi built in. You shouldn’t have any issues - even if you did go for the HD2 mini…