I would iso max Hood and Lazy Cap - you have them covered perfectly and should be able to use Hood and Thor to achieve top 25 / 100 pvp finishes (they are good on offence and people will think twice about attacking you) and LCap and Hood to do well at PvE. Yes it will probably up your scaling but you will be much more competitive (and I would not be patient enough to wait!).
Proper placement of LCap pre battle will mean he tanks some colours for Hood (soaking up damage for him).
There is an argument (though I didn’t do this and have done fine) to keeping Hood slightly below max level (afraid I don’t the ideal level but I have kept Falcon at 127 so that LDaken will tank 5 colours for him so that may work here too) so he matches fewer colours and can hide at the back, though not giving him the maximum health makes him less of a deterrent in PvP.
Eventually you will want Thor to be a 3/5/5 build (I assume from the below that he is iso maxed).
I do not think Sentry should be a priority for you. He was nerfed so that he is now not a PvP essential and his current use seems restricted to quite limited situations (dealing with very difficult PvE battles by use of his red, but the same can be achieved with others like LCap, Hulk, Cap Marvel etc).
Yes I would ISO max Lazy Cap and Hood. Lazy Thor is also worth doing if you have not done so yet, though you do not have him at the ideal build (3/5/5).
XForce is only worth building up if you have him at at least 5 covers in green or black and ideally he should be max in both. Yellow is useful but not essential. The best XForce build is 5/5/3
As I see it the main advantage of Sentry is much like Deadpool - to make other players pick someone else to attack instead of your team. Both can be hard to get away from attacking without serious injury which means using up heals.
On the attack I am with everyone else he just has no staying power for multiple fights and kills the rest of the team (except self healers). You can however use him as a HP shield and just ignore his powers in favor of others.