It’s great you’re able to give them a bigger space!
As your piggies are two boys, A 2x4 is the minimum size for a boar pair so they might be ok but it may also be a big tight for them. You will have to see how things go. The recommended size for two boars is a 2x5. Boars can struggle if they dont have enough room and it can affect their relationship. Although if the cage they are in now is already smaller than a 2x4, then a 2x4 will feel like a palace to them!
My two boys originally had the equivalent of a 2x4 space and it lasted a couple of weeks before it was obvious it was too small and they needed an extension
It can suit some piggies, particularly boars and particularly teenage boars, to not use food bowls or hay feeders at all. Simply have an area where a large pile of hay is just put in loosely on the floor so they can eat freely, play in it and lay in it. You can also scatter the veg and pellets directly onto the bedding or into that big pile of hay. This stops any issues with food hogging but also provides them with a great deal of enrichment and keeps them occupied. They will have to use their senses to search through to find the food.
Whatever items you do buy, ensure you buy two of everything. For boars, having to share items can be problematic and you can find bickering and issues occuring (particularly as they are to be in a period of reestablishing themselves due to having a new cage).
Also ensure each hide has two exits. Don’t use enclosed pigloos as this is how fights can occur if one piggy gets trapped inside by the other piggy.
As they are boars, then changing their cage is going to cause them to reestablish their relationship and territories. You are going to see a period of increased dominance between them. In well bonded pairs this will calm down after a couple of days to a couple of weeks. In pairs who are less well settled, it can cause problems - It can therefore be a good idea to use some soiled bedding from their old cage. This will help the new cage smell of them and will make the transition to the new cage easier.
Chew toys are not essential. They don’t actually wear their teeth effectively in any event. The only thing that works to grind down their teeth appropriately to help prevent dental issues is eating lots of hay (and fresh grass also has the same effect on the teeth). Chew toys do not wear the molars at all.
Cage Size Guide
A Comprehensive Guide to Guinea Pig Boars
I would stay away from the artificially colored wood toys from stores, only the natural wood ones.