and could anyone also maybe answer my other question in the boy’s category please?
I don’t think any of these are getting too popular. I love [name]Max[/name] and [name]Theodore[/name], although you could always use Theodric instead. I think [name]Felix[/name] is definitely underutilised.
I think the only one on the list that is too popular is [name]Max[/name]. Everyone knows several Maxes now, and worse, I keep meeting dogs and cats with the name. (It’s my boyfriend’s nickname and sometimes it’s annoying that there are so many… It gets confusing when people talk about a [name]Max[/name] and I don’t know which one it is.)
My favourite on your list would be [name]Felix[/name].
Big [name]Max[/name] fan 
Considered [name]Theodore[/name] nn [name]Theo[/name] to go with our son’s name but it doesn’t quite match up. Like [name]Felix[/name] but its my boss’s name and that’d be weird. [name]Jude[/name] is handsome but not my style. But to answer your question, yes, I think they’re all growing in popularity but none of them are too bad yet.
I don’t think any are getting exceptionally popular all of a sudden. [name]Jude[/name], I’ve heard quite a bit recently on baby girls, and it’s been steadily climbing the charts for the past 10+ years, but is slowing down in the mid 100s ranking. [name]Max[/name] is more popular for boys, but it’s been pretty steadily around the 100th most popular name for the past couple of years. [name]Theodore[/name] has similar rankings to [name]Jude[/name], but has been gaining popularity even slower. [name]Felix[/name] has also slowly gained popularity, but is still fairly uncommon in the US.
(all of these statistics are in the US only, and I just realized you’re in [name]England[/name]. I believe [name]Max[/name] is less popular in the UK, and while the other three names are more popular (in the top 100), they’ve had a similar pattern of increased popularity as they have in the US).
I think it really depends on how you define “popular”.
In Germany for example (the government doesn’t keep statistical records on given-names) their are records of [name]Max[/name] and [name]Felix[/name] being among the top 100 names (variants are counted as one - i.e. [name]Theodor[/name],[name]Theodore[/name], [name]Theodoric[/name]) since the middle ages. Usually I’d consider top 100 to be fairly “popular”.
I’d think that [name]Felix[/name] and [name]Max[/name] will probably become more popular in [name]England[/name] and the US in the next few decades. [name]Both[/name] are short, easy to pronounce, spunky and have the funky x - yet they still are classic and not trendy. You should consider how you would feel about it if the name jumped 50 slots up in the next 5 years. I don’t know where you live but sometimes it’s helpful to consider how many kids in your son’s class might have the same name.
Stats from [name]England[/name] & [name]Wales[/name]. I think [name]Max[/name] is already there (and this is without any other longer forms of the name), the others are fine.
[name]Max[/name]:
1996: #56 (1192 babies)
2003: #34 (2154 babies)
2010: #23 (2707 babies)
2011: #20 (3043 babies)
[name]Theodore[/name]:
1996: #209 (152 babies)
2003: #165 (242 babies)
2010: #137 (437 babies)
2011: #124 (505 babies)
[name]Felix[/name]:
1996: #210 (149 babies)
2003: #152 (301 babies)
2010: #122 (511 babies)
2011: #131 (492 babies)
[name]Jude[/name]:
1996: #654 (24 babies) - this was before [name]Jude[/name] [name]Law[/name] got very pop
2003: #97 (537 babies)
2010: #86 (575 babies)
2011: # 83 (764 babies)
[name]Max[/name] is popular here in the States. The others not as much. I would say that what’s popular on NB doesn’t always translate exactly [name]IRL[/name]. All four names are very popular on NB, but like I said maybe not as popular in the real world.
I hear [name]Jude[/name] and [name]Max[/name] quite a bit on tv and around town. I think we will hear more of [name]Theo[/name] and [name]Felix[/name], but I don’t think they will get huge.
I actually really like all four of your names, and I don’t find any of them to be SO popular as to be unusable… but [name]Max[/name] strikes me as the most popular of the four. I like [name]Maxwell[/name], which is slightly less popular and still leads to the same nickname.