Does the preamp have an effects loop? Yes? Use it.

I am thinking about getting the GT Brick, would this be applicable?

The Brick is a great piece of gear, very useful. But is this tempo-tapped-delayed uke going to be a live gig thang? If so, I think that the insert loop on a typical PA mixer would be a better route ( as per DD's suggestion), because the Brick has no insert loop. You also run into gain issues because your typical stompbox delay pedal is designed to be used with a relatively low-level electric guitar pick-up. Running the output of the Brick into a stompbox is sure to overdrive the bejeebers outta the pedal. And digital delays do NOT like that-they sound like crap when they get pushed too hard. If you end up using a mixers' insert loop to feed and return the delay pedal's signal, you are sending it a hot signal, but not nearly as hot as the output of the Brick...

could i use an impedance transformer cable ?

Is this for your live gig at the shore? What are you going to be using for vocals? Most duo's use a powered mixer, or something similar. Or is there a house system?

not sure of all that yet, right now we are just getting songs together, i have a cheap phonic powered mixer, and i don't even know what my buddy has.

i don't even have the brick or a delay pedal yet, but i like to make informed purchases.

the more gigs, the more money towards the goodies!

You are almost better off in this case to buy a rackmount unit. A nice used Lexicon or something that has tap tempo. And use it through the inserts on the board for that channel. Or if you have enough subs return it through a channel and assign it to whatever you want tot use it on. Much better sound and sound control.

Do you plan on doing this for recording, live, or both?
Do you want to have both a clean and delayed uke?

Just some questions I came up with along the way...

Tbird "i don't even have the brick or a delay pedal yet, but i like to make informed purchases."
Good thought but in order for someone to give advice we need to know exactly what you are trying do. Live (PA or just a stage amplification for the uke alone) studio or potentially both. I think Moonbaby is correct a guitar pedal is not a good choice for a mic'd application and was thinking more along Davedog's rack mount suggestion. The key question about this is what exactly will you be using for amping? Your Phonic mixer probably does not have individual send/returns and if it only has a master effects loop (if it even does) then the delay will be applied to everything coming from the amp unless each channel has efx control. Even if that is the case and you are going to use this at the same time for vocals I doubt you would want to run the vocals without at least some reverb. So you really need to think how the entire chain will work in the context of all amping and/or sources required for the gig or purpose.
Perhaps you should put together a list of any potential equip you might have access to and a simple plan chart of what you are trying to amplify, like 2 vocal mics, guitar, etc.

i dont need the delay now, but in the future.

the cover project is just my friend and i playing acoustic bar tunes.

the delay effect would be for live use, so i definitely need a tempo tap feature. i have an ok delay plugin so wouldnt need it for recording, .....but the more choices the better.

another idea is to just get a uke with pickups built in just for live use, and use my acoustic one for just that or in the studio.

to sum up, for right now, i just need to mic my 2 voices and two guitars (one of them the uke)

the phonic mixer has a delay effect, its not the best but it will get me by for what i need right now.

for the eventual uke delay i want control over all aspects of the delay, which the mixer cant do, but there is no rush just yet

all very good thoughts though!

If you did get an electric uke (pickups anyway) then a guitar pedal will work fine.