Up air to rest combos but you usually have to jump on the earliest possible frames to get a realistic window and you also should be trying to connect with the upmost part of this hitbox, it has one near the top of Jiggs. If you do both of these things you can increase your window to land rest off an up air by a lot.
Up tilt combos into rest, but its very low percent only and isn't very good vs characters with strong punishes, I like to up air off my utilt instead as its a stright profit of 9% damage.
You can Fair to rest with weak fair, I've done it multiple times and it does register as a consecutive hit in training. Weak nair can work as well but its very impractical and difficult. The percent window for nair is also super tiny.
I'm wondering if Jiggs can do any jabs into rest at higher percent assuming knockback works the same as it does in other games, since rest comes out presumably instantly its something we can try. Total speculation here though.
Oh, up air to up tilt combos into rest as well and is heavily dependant on Jiggs current percent.
I don't know how rage effect mechanics work in training. In conclusion, yes she can combo into rest but its not very good most of the time, as stated earlier, rest is best used out of shield.
I can't see her getting combos from any other moves she has, like throws, smashes, or ftilt/dtilt.