Just buy Linksys SPA3000 SPA-3000 as your FXO gateway to your UNIFI VOIP phone, I know that the intention is to utilizing TM's free calls to TM network.

Last time I have setup an asterisk (dial plan rules) to connect to my Linksys SPA3000 SPA-3000 for Unifi for SIP trunking (TM-to-TM free calls), International calls to voipstunt as SIP trunking (Free HK, JP, Sing etc), trunk to YES VOIP for 018-018 free calls and Google voice US number (free US-to-US dialing with 1 US #).

Now the Linux Asterisk motherboard is spoiled,   still not yet bring the box up.

Nope, you can do VLAN by connected to a VLAN switch

What is your ultimate goal here?
my previous setup was to use the SPA3000 as one of a SIP trunking for 03 number (because it is free) for my asterisk

For asterisk, you can setup unlimited account (SIP extension, aka VOIP account)

FYI, SPA3000 has only 1 FXO and 1 FXS port

Then u need to have 2 SPA3000, each connect to each VOIP-RJ11 port; 1 asterisk via these 2 ATA devices as SIP trunk; and create calling rules yourself inside the asterisk.

that's all.

If you wanted to to use in 2 different location u must have 2 ATA.