4 matchdays in (some teams already halfway through) and here is how the groups look like
Group A
England were vacant due to the NL so the big winners this window were the Czechs who got the 6 points in their two home matches against Bulgaria and Montenegro, Kosovo keep pace with 2nd place as they earned 4 points in two away games. You fully expect England to cruise in this group and I don't really see them dropping points anywhere (maybe in Czech). The key matchups will be CZE-KOS and they play each other next MD in Pristina.
Group B
Portugal were vacant but they will need to pick up their campaign as remember they only have 2 points from 2 matches. Ukraine won both their home games and top the group on 10 points with a 5:0 hammering of Serbia being the highlight. At the moment Luxembourg/Serbia are joint 2nd
Next matchday is Serbia-Portugal, really the loser of that match, if there is one, will have a hard time finishing 2nd, but both have the NL route
Group C
Northern Ireland top the group and are perfect after 4 rounds, but somehow the fixtures have them finishing their campaign against Germany and Netherlands twice. However, if they can nick a result against one of them, they might have a chance. Germany with two easy wins this window should qualify as they already beat the Dutch earlier.
Group D
Ireland remain unbeaten after their draw in Denmark and easy home win over Gibraltar and have a comfortable lead at the top for now but their main competition (Swiss and Denmark) have game(s) in hand. This is another group where three teams have the NL route so not the end of the world if one of Switzerland/Denmark miss out the top 2
Group E
Hungary the surprise early group leaders winning three in a row after starting off the campaign with a defeat. Wales lose both their away matches and now the pressure is on them. Next matchday is Slovakia-Croatia where the loser might have problems going forward. Overall very tight group with Azerbaijan being the minnows. Anybody who drops points to them is in trouble and so far the home teams have won all their matches against non-Azeri teams
Group F
Spain are perfect after four rounds with their nearest competitors already five points behind. Norway on 5 points can only hope for 2nd place but they still go to Sweden and Norway later in the campaign so tough to see them in the top 2
Group G
Poland perfect after 4 matches and yet to concede a goal in whats looking like along with Group A the softest group. 2nd-5th is separated only by 3 points with Macedonia the only team with the NL route to fall back on. The big winners were Austria, who lost their first two matches but won both their June fixtures and are expected to win their next one with Latvia at home
Group H
In typical Turkey fashion they beat France but then lose to Iceland a few days later (which has been their bogey team in recent qualifiers). Turkey, France and Iceland all on 9 points with Albania on 6 so pretty tight group. The fixtures favor France who will play Andorra home, Moldova twice, Turkey home but yet still have those trips to Albania and Iceland. Likely Iceland-Turkey will be fighting for that second spot
Group I
Belgium perfect and again hard to see them dropping too many points in this group. Russia had an easy set of fixtures on won them both and are in 2nd place only 3 points above Kazakhstan and Scotland. Scotland have the NL route to fall back on, but their next match at home to Russia will determine how realistic their top two chances are
Group J
Late winner for Italy gives them 12 points from 4 and they should qualify but I wasn't impressed with them today. Finland definitely one of the surprise packages so far winning 3 of 4 to open their campaign and they have some separation on their most serious rival Bosnia who are only on 4 points (but have a home heavy schedule to close the qualifying). Greece lost back to back home games against Italy and Armenia both times conceding 3 goals, they have fallen off the football map really. Armenia are technically in this, but their next two matches are against Italy and BiH, if they can get something from those, then I will take them seriously